Garmin Fenix 5 Review including | 5x | 5s | Forerunner 935 |

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This Garmin Fenix 5 Review covers, in detail, the full Fenix 5 range which includes: Fenix 5S; Fenix 5X and the Forerunner 935.

Garmin’s high-end product range has just got considerably bigger

Garmin Fenix 5 Review Garmin Fenix 5X 5 5S Forerunner 935 Review

The Fenix 2 was OK back in the day. The Fenix 3 eventually became outdoor, multisport greatness selling in large volumes for Garmin. The Fenix 3HR added optical HR to the mix. The super-expensive Garmin Chronos is a “Fenix 4 dress watch” in everything but name. Then there is the real successor to the Fenix 3 which is the Fenix 5.



Except it isn’t.

That’s because there is the Fenix 5S – aka the ‘small-wristed one’. Then there is the Fenix 5X – aka ‘the map one’. Then there is the Forerunner 935 which REALLY IS A Fenix 5 – aka the ‘lighter, triathlon one’. Then there is the plain old Fenix 5 which really is simply ‘the Fenix 5’.

The joke is that the Forerunner 935 is the Fenix 5P (plastic) or Fenix 5T (triathlon). Ha ha unleash the mirth. But seriously when you read this review just substitute 935 for ‘Fenix 5’ and it’ll still hold.

The software is virtually identical except the 5X has map functionality.

There are also various strap, screen and bundle options but my head is about to explode just getting to grips with 4 models so I won’t be covering those other variations too much.

Now you know.


Simply ‘it’s all got a bit better’ compared to the Fenix 3HR. There are enough differences to genuinely warrant the Fenix 5 being called a new version. I’ve covered this before, here, comparing to the F3, but will include the highlights below for completeness. The following are the most important additions for the Fenix 5/935 in my eyes:

  • HARDWARE – More powerful and has a 64 colour 240×240 pixel screen (218×218 on the 5S). This extra power is for the new generation of CIQ apps. There are 5 buttons but, wisely, no touchscreen.
  • HARDWARE – The optical HR unit gives 247 readings and there are aesthetic- and supposed-technical improvements. I have NOT had a great experience with the F5X’s oHR.
  • HARDWARE – The battery lasts longer, probably upwards of 20 hours with GPS+HR in a good scenario but that can be further extended threefold with ULTRATRAC.
  • CONNECTIVITY – Native support for MOXY/BSX muscle oxygen sensors as well as Bluetooth sensor support. Some Bluetooth sensors may have connectivity issues and running power is still not natively supported. WIFI connectivity is only on the higher-end models.
  • USER INTERFACE – Broadly in line with the CHRONOS/F3 look and feel. Garmin have pretty much ‘nailed’ the interface for 5-button based watches over the last 2+ years, IMO.
  • PHYSIOLOGY – Working with Firstbeat, Garmin have added some clever new stuff including Training Load and Training Effect, the latter being expanded to now include Anaerobic training effect. Cycling mode also estimates FTP.
  • NAVIGATION – some time and distance and POI tweaks
  • MAPS (5X) – A real onboard map allows ‘proper’ navigational functionality akin to what you would find on your car’s SATNAV.

The Fenix 3’s GPS/GLONASS/GALILEO/BEIDOU chipset of the MediaTek MT3333 is probably unchanged (TBC).

But a key point to bear in mind for those of you new to the Fenix are the pre-existing features. It really does do pretty much 99% of what you would ever want.


OK let me start off by saying that these are the best, and nearly most expensive sports watches ever made. It would be crazy of me to say anything else. I’ve bought one, no Garmin freebies or loan devices or bias here. The Fenix 5 is GREAT.

However this review will dwell a little on the more negative aspects of the Fenix 5/935. You can read lots of positive reviews all over the internet. However out of respect for you wanting to do your research properly, I’ll try, at times, to present some of the real facts (as I see them).

You say, “So…. it’s GREAT and yet you’re going to be negative???” Yes I am, a little, but I can also draw your attention to the Garmin forums where there are quite a lot of people with issues.



Fenix 5 Review Garmin Fenix 5, 5X, 5s, 935 Review

There are bits of documentation that you will never read. You knew that.

The salient points are that you will get the watch of your choice and yet another style of USB charger.

Well, not quite. You also get removable straps.

Fenix 5 Review Garmin Fenix 5X 5 5S Forerunner 935 Review

  • STRAPS – At first I thought these were a bit of a gimmick when first released last year but I have to say I have come around to like the idea. You have your stinky, sweaty strap for sport which you then quickly change over to your posh work strap once you leave the gym. Actually that is a GREAT way to make the Fenix 5 a 24×7 watch. Beware they come in 3 widths but the Fenix 5 is the same as the 935 at 22mm. Also of note is that the strap release mechanism looks to be integrated with a bike Quick Release Kit for the 935 and the F5 as they are the same width – definitely not compatible with 5S/5X

Fenix 5 Review Garmin Fenix 5, 5X, 5s, 935 Review

  • CHARGER – It fits in either way round. It was a bit stiff at first to insert and remove from the rear of the watch but then fine for just over a week. BUT 3 weeks after that I have intermittent occasions where a data connection is not made. In itself this is a reason for me to return the Fenix 5 – it will NOT improve over time will it? TIP: Check your Fenix charging port is free of sweat/water as this DOES limit connectivity. I blow into the hole EVERY time before connecting the cable.
  • CHARGER – It’s annoying that it’s not micro-USB BUT, in reality, micro USB will fail over time once it gets repeatedly used and repeatedly wet. On that point, I’m not sure how the existing F5’s charging port will fair over time either as passing an electrical current through a confined area containing salty sweat could be a perfect recipe for corrosion. Time will tell…
  • You can charge the F5 and use it at the same time in your ULTRA. However that is extremely tricky with the charging port being where it is on the rear. Tricky. But not impossible…a wearable cradle was ‘developed’ for the F3. One will come for the F5 eventually, a cable with a different end and a bit of padding will do it!

The charger has a design fault – in my opinion


In this Garmin Fenix 5 review we go to great lengths to cover the functionality and the accuracy. Looks and usability are important too.

I don’t particularly like the Fenix 5’s rugged looks. It’s Ok. I’d wear it. Personally, I prefer a smoother bezel devoid of bolt heads.

The buttons are OK to the touch, they could give more of a responsive feedback but they’ll do.

On the other hand I DO like the orientation of the buttons. Couple those with the software interface and the overall ‘user experience’ with the Fenix 5 is excellent.

Fenix 5: Nice and HIGH on the usability stakes.

The Sapphire glass on the higher-end models seems to be slightly more reflective than others. But I’m probably imagining that. At least they won’t scratch easily but a pain in the proverbials to take pictures for this review 😉

The standard band is nice. Although, as I say above, you can easily change that to one of your choice.

The optical HR sensor array on the rear is almost flush to the skin and is comfortable. Both the sensor array and the charging port will leave a mark on your skin if the strap is done up tightly.

My main gripe, however, is with the screen resolution. Whilst the screen resolution of the Fenix 5X/5/935 are IMPROVED over the Fenix 3 it is still not as good as Suunto’s SPARTAN (the latter at 320×300 pixels). However even that comparison is somewhat moot. NEITHER the Suunto nor the Fenix 5 are good enough to properly render a decent imitation of an analog watch face. I struggled to find a single watch face on the whole of the CIQ site that I thought looked OK.

A desert of aesthetic watchfaceness exists on CIQ, in my opinion.

full-day-watch-faceDon’t get me wrong. Some of the apps and watch faces for sporting data are great. In a sporting scenario, watch-face aesthetics only matters to me a little bit. But when I wear a watch, aesthetics matter to me a lot especially when I’ve spent well over £/$500.

I only found one single watch face that I thought was aesthetically acceptable to me! And I was the 2nd person to download the aptly named FULL DAY , presumably 2nd after the author CLIV3RUN!. As of 8May it’s up to 17 downloads. Does that suggest I have poor aesthetic taste?

Fenix 5 Review Garmin Fenix 5X, Suunto SPARTAN SPORT WHR, Garmin Forerunner 235
Garmin Fenix 5X, Suunto SPARTAN SPORT WHR, Garmin Forerunner 235

The Fenix 5X is very similar in size to the previous Fenix 3HR. The 5 is a tad smaller and the 5S smaller still. The 5S is pretty much the same size as the round Garmin Forerunners and some Polars and Epsons and others. The bottom line is that you’ll need to try one on if you are concerned about how the size might look. I’m thin-to-average-build for someone who is 5’9″-5’10” and the 5X does look a little big on my relatively thin wrists…but fine nevertheless.

This simple table gives you an overview:

Fenix 5 Fenix 5S Fenix 5X Forerunner 935
RRP >US$600++ >US$600++ US$800 >US$500++
Weight 87g 67g 98g 49g
Physical dimensions 47x47x15.5 mm 42x42x14.5 mm 51x51x17.5mm 47x47x13.9mm
Display size, WxH 1.2” (30.4 mm) diameter 1.1” (27.94 mm) diameter and lower resolution 1.2” (30.4 mm) diameter 1.2” (30.4 mm) diameter

Here you can see the Fenix 5X and the SUUNTO SPARTAN ULTRA are both thick beasts.

A minor point to make would be that the Fenix 5/935 can sometimes have a VERY SMALL lag when a button is pressed. It’s certainly MUCH more than acceptable and SEEMS more responsive than some of the SPARTANs (although if you time it, the F5X IS slower 😉 )

Garmin Fenix 5X 5 5S Forerunner 935 ReviewTHE GARMIN WORLD OF DATA WONDERFULNESS

If you are new to Garmin then there are a few basics to their ‘world of data’ that you need to get straight.

  • Your Fenix 5/935 – Yep there’s a lot of data on there. We’ll come back to that
  • Garmin Connect Mobile app – it’s good for iOS or Android and is generally solid and professionally delivered. Garmin has one app that handles all their range of products and that is no mean feat as their products target very different consumers who have very diverse app needs ie it’s bloomin’ complex. There are lots of pretty summary graphs telling you how you have done be that in terms of steps or your sporting performances. If you have 5 minutes per day to review your activity and sports then Garmin’s app is all you need. If you want to start analysing your sporting endeavours in detail then you need to turn your attention elsewhere and, most likely, away from Garmin.
  • Garmin Connect – on the web. Duplicates much of the information on the app and provides superficial, graphical overviews of some of the more unusual data (like Vertical Oscillation). Allows routes and structured workouts to be created and passed to the Fenix. Other bits too, of course.
  • Garmin Express – You can synchronise your Fenix with Garmin Connect either over WIFI or using the Express computer software. For firmware and map updates I suggest you use Garmin Express, indeed I think you have to now.

All of this software infrastructure behind the watch is very good on the whole. As I said it’s not great for detailed analysis but also I would say that the WIFI connectivity and the BLUETOOTH connectivity to your smartphone might not be as reliable as you would hope. Some of you will have no issues whatsoever whilst others will simply give up on trying to permanently link to your particular flavour of Android smartphone.

For those of you who want to join other sporting data worlds then there is market-leading integration between the Fenix 5 and STRAVA and an automated upload with Training Peaks. You will see competing products offering STRAVA connectivity but beware…some competitors to Garmin just mean that they will send your completed workout files automatically to STRAVA. On the other hand with a premium STRAVA account and a Fenix 5 you get the integration with STRAVA LIVE SEGMENTS on your Fenix 5…cool!

Of course just like many other apps, Garmin Connect Mobile and your Fenix can work together to keep those SMS, app and missed call notifications popping up on your screen.

To some extent, going with Garmin will future-proof all of this for you to a better degree that with many other smaller vendors. If a super-new app is invented in 12 months time that every cyclist just HAS to have then you can bet that Garmin will be one of the first to integrate it well with the Fenix 5.

Garmin Fenix 5X 5 5S Forerunner 935 Review10,000 STEPS, 14 FLIGHTS OF STAIRS AND A PIZZA

This Garmin Fenix 5 review will now cover the non-sporty stuff: steps, stairs, sleep.

Garmin doesn’t really provide any nutritional guidance within their environment, for that you would link Garmin CONNECT to your MYFITNESSPAL account.

However Garmin do cover activity and sleep tracking very well. You can see from my day below that I had an OK sleep then sat around most of the day writing this – apart from a quick run just after lunch time.

Your heart rate is periodically and permanently logged every few seconds and you can see your HR over the last 4 hours on the watch.

Garmin Fenix 5X 5 5S Forerunner 935 Review

Garmin’s STEPS are as good as anyone else’s. If Garmin say 9600 and Fitbit say 9850 then it doesn’t really matter. Garmin also have a more nuanced, and cleverer feature, ‘Intensity Minutes’ which looks at your average steps per minute or HR compared to your resting HR. These comparisons determine if you are doing something a little more strenuous than simply walking. Linked to this is MoveIQ where the device automatically detects the type of activity you are performing eg walking/sleeping. All of these ‘little features’ are individually trivial but together they add up to a rich experience. And there’s more, Garmin use all the raw data to give you trends and insights into your activity-levels and sport-levels.

Whilst Garmin’s efforts here are market-leading there is still one major omission:

‘Proper’ overnight recovery and readiness is very important for even a casually serious athlete and/or someone concerned about their sleep quality. The Fenix’s 24×7 heart rate tracking goes a little way towards indicating your readiness and overnight recovery. Only a HRV HR sensor can do this ‘properly’. Garmin isn’t there yet with a commercial optical HRV offering. Or at least it hasn’t yet been enabled on current hardware. You could wear a chest strap all night or do a waking chest strap measurement but, chances are, you won’t.

Note: Other vendors such as WHOOP and PULSEON have commercial HRV based on optical technology but only working OVERNIGHT for recovery analyses. I would expect Garmin to have such an overnight offering in 2018 likely added to the Fenix 5 PLUS. CIQ apps exist pre-installed on the F5 for HRV STRESS/WAKING HRV, which is different (but also useful).

Garmin Fenix 5X 5 5S Forerunner 935 ReviewSPORT USE – GENERAL

There are many aspects of the FENIX 5/935 that cross over all the key sports profiles: run; bike; swim, pool and OWS; variations on those like MTB cycling; and combinations as a multisport session. This Garmin Fenix 5 review  won’t cover other sports like skiing, SUP, hiking or custom. For each sport profile you can have several screens with any number of data metrics arranged in several ways (images below) and there are also ‘special’ dials and charts everywhere.

Starting a sport – you can just press ‘go’ with your new watch!!

Instead you could choose to follow a structured interval workout that you created in Garmin connect and synchronised to your calendar. Or you can create a simple interval workout ‘on-the-fly’. Or you could choose to race an activity (yours or someone else’s) for that elusive PR/PB around the park. There might also be slightly more obscure options like performing a test (LTHR)

There are a whole host of things that can happen whilst you are exercising. You can insert manual laps or have an automatic, distance-based alert, and along a similar vein you can cross one of your STRAVA segments and be notified whilst running/cycling. The Fenix 5 even allows you to customise the LAP message that pops up. Nice.

It’s not a garden of sweet-smelling roses though. Auto-lapping by time or position are still not possible. And it is still not possible to insert laps within intervals – essentially a manual ‘lap’ just ends the current ‘thing’, be that an autolap or a multisport.

These trivial-sounding features would probably be quite complex to integrate into the entire Garmin ecosystem if you think about: the changes involved to the FIT file specification; the presentation of laps on Garmin Connect; and the integration of two tiers of laps into firmware button presses to name just three.

Garmin Fenix 5X 5 5S Forerunner 935 Review
First swim of the week 😉


However the ALERT functionalities are pretty awesome. Tiger close by? Don’t worry, there’s an alert for that!! Maybe not but there are alerts for: POI proximity (eg tiger sanctuary); HR; pace, elevation ,cadence, and all the basics. You can set alerts for run/walk or to remind you to drink/eat after a certain distance or certain amount of time. I used to use alerts quite a lot but have found over time that the extra key presses deter me from bothering to set them up. The two exceptions here would be for a HR cap and a power cap when I want to rein in my efforts in longer races.

The only alerts that I could think of as missing were power-based alerts in running mode.

After your exercise you get a pretty awesome set of summary pages. They’re not my kind of thing as I would look at the numbers later but many of you want the info there and then. Garmin deliver well here with subtle variations between sports:

  • Summary totals/averages of everything you’ve just done
  • Lap details of the same info
  • A zoomable route map of where you were (5X)
  • The (an)aerobic training effects and some words explaining what aspect you improved upon
Garmin Fenix 5X 5 5S Forerunner 935 Review
There is a further page on the watch with a wordy description of this summary
  • Time-in-zone chart eg HR or power.
  • Elevation plot
Garmin Fenix 5X 5 5S Forerunner 935 Review
Hmmm…could have sworn I was in Zone2…let’s come back to that


The Fenix range is great for running. You might say that the 5X is a little heavy but the 5S and 935 are much lighter.

As we’ve already alluded to, you customise the screens you want for running. You can have many screens, with many orientations, with the data fields that you want.

You can change the data screen during your run just as you can change other features such as turning the running metronome on/off and turning alerts on/off.

Like any sports watch you can flick between screens as you exercise.

I tend to mostly group together metrics for similar time periods. Thus my main screen would comprise: instant running power (STRYD); instant pace; instant HR; total duration; and instant cadence – except I can’t do that as the Fenix will only display 4 fields and I would like 5 😉 The Suunto SPARTAN can display more fields (7) and apps from Garmin CIQ can also display more depending on the app.

Then I would have a screen for, maybe, lap information or start-to-present aggregated info – I wouldn’t use that screen too much. Sometimes, when training, I have the clever dials that show running form metrics like ground contact time. Although I’m never too sure what to do with those metrics.

You can change the routing options if you are navigating whilst running and you can, of course, pop the backlight on at night so you can read the numbers on your wonderful device.

Generally the screen is easy to read but, at the same time, there is a lot of wasted space. An option to turn off or shrink the name of the data field could be handy when you just ‘know’ what the metric is. [I seem to remember that being an option on another Garmin? or was it another manufacturer?]

Here are some of the many other run features:

  • Running Apps from CIQ – eg STRYD
  • Auto pause
  • Auto climb
  • 3D speed (what is this! – A:here)
  • 3D distance
  • lap key (enable/disable)
  • Auto scroll (between pages…annoying)
  • Segment alerts
  • GPS vs ULTRATRAC (longer battery life, lower accuracy) vs GPS+GLONASS (less battery life, increased likelihood of accuracy..maybe)
  • Powersave
  • Screen colour changes.
  • Lactate threshold test
  • Distance/time/pace targets
  • Race an activity
  • You can now even turn HRV (chest strap) on and off from the menus

Garmin Fenix 5X 5 5S Forerunner 935 Review

You could even go for a run and get some training in after you’ve finished playing with all those functions…

Some notes on running

  • You can run without getting a GPS lock first. But it’s not a good idea. Your pace/distance figures will be HIGHLY inaccurate (or non-existent) and furthermore even once you get a GPS fix you will find inaccuracies for a ‘while’ longer. Get a HR lock and GPS lock BEFORE you set off…always. It’s quick to do.
  • If you plan to train using PACE or SPEED. Then you MUST buy a footpod to get a reasonably accurate figure for instant pace. I’m getting fed up with saying that. A Garmin or non-branded footpod will improve matters BUT STRYD is the MOST ACCURATE (and most expensive). You’ve spent all this money on a top-end watch, you can afford a footpod of some sort.

What’s missing when running?

A: Not a lot!

  • Native STRYD support would be ‘nice’ but it’s not necessary.
  • Better instant pace accuracy would be very nice but I use STRYD so I don’t have that problem (you WILL…sorry!).
  • Laps within intervals would be nice to have.
  • Some means of charging whilst in use for ULTRA runners would be nice to have for that small sector but the current battery specification is market-leading and will cover many ULTRA durations (70-odd hours with ULTRATRAC)


The Fenix 5/Forerunner 935 is more than adequate as an advanced cycling watch but it will never match a top-end, dedicated cycling device like a WAHOO ELEMNT or GARMIN EDGE. Such devices have a better, larger screen amongst other PRACTICAL benefits such as the number of metrics permitted on any one screen.

As we shall see later, the Fenix 5/935’s GPS and oHR accuracy when cycling is NOT market-leading. However the Fenix 5/935’s cycling functionality is immense. But it’s not all about size and what you can do with it…there could be a joke there somewhere.

There are a very similar degrees of in-ride options as there are for running. So you can cross segments, change screen layouts and execute intervals just as you would with running. And more besides.

Garmin Fenix 5X 5 5S Forerunner 935 ReviewCycling usage allows you to also follow a guided test to determine your FTP – a chest HRM; a previously calculated VO2max; and a power meter are all required. You can accept the FTP calculation that Garmin give to produce your training zones. Personally I use the free and awesome Golden Cheetah software that produces a modelled FTP (mFTP) based on all my performances. Golden Cheetah also seems to produce a more accurate full CP curve for me rather than one calculated by a single 20 minute test.

The alerts are as before with running but this time you CAN get a power alert..handy.

Of course there are also very many cycling-specific metrics related to POWER, GEARS and other exciting things:

  • Power includes: pedal smoothness; torque effectiveness; 3s, 10s and 30s averages; and balance metrics…LOTS of metrics.
  • Gear info includes: battery, ratio, front, rear, etc
  • Intensity Factor, TSS, NP (including lap variants)
  • Muscle Oxygen (MOXY, BSX)
  • FTP related
  • Advanced Cycling Dynamics metrics for the Vector2/3 including PCO, PP, PPP, standing/seated. You have to be REALLY into your cycling data in an overtly nerdy way to want these!
Garmin Vector 2
Vector 2

Then there are also Garmin social features that include LIVETRACKING and GROUPTRACKING. With your smartphone, people at home can see where you are; or, with GROUPTRACK, you can see everyone in your ride who has enabled livetracking OR grouptracking. Clever stuff.


Garmin Fenix 5X 5 5S Forerunner 935 Review

A ‘proper’ cyclist will probably always have: ripped and bloodied lycra; road rash; AND a cycling head unit. It just makes more sense to have the data on your handlebars or the navigation device on your handlebars. It also makes more sense to have a bigger screen for both those tasks. But if you are a cyclist who also wants a 24×7 watch or a multisport athlete then something like the Fenix 5 gives you ALL the functionality you would ever need PLUS the wrist-based wearability.

Some of you will be lured by the ability to broadcast oHR FROM your Fenix 5/935 to your ‘head unit’. Clever! But tread carefully young padawans. If rubbish HR is being read then rubbish HR will also be broadcast to your head unit. DON’T throw your chest strap away yet…wait until you have found out how the oHR works for you WHILST CYCLING.

Some of you using obscure Bluetooth-only PMs in a non-Garmin environment eg Polar, Suunto or simply Bluetooth PMs linking to STRAVA on your smart phone will be tempted by the Fenix 5/935’s ability to directly connect to Bluetooth sensors. Check the compatibility of your PM or sensor first but, yes, that could be a great move for you.

If you are like me and often find it easier to wear your watch on the underside of your arm whilst using TT bars then be warned that you will probably have ‘different’ issues with reading oHR from the ‘wrong’ side of your forearm.

Q: What’s missing with cycling?

A: Nothing, given the format/size inherent in a wrist watch. The 935 can be handlebar-mounted with Garmin’s quick release kit, which would aid some usability constraints of wearing on a wrist and navigating. The Fenix 5 (not 5s, not 5X) MIGHT also fit the same mount. A super cheap wraparound mount will also work – I used a simple old Polar mount from the 18th Century…it worked fine.


Now the Garmin Fenix 5 review will turn to triathlon’s poorest sporting member…swimmingGarmin Fenix 5X 5 5S Forerunner 935 Review

The Fenix is a great swim watch. It is packed full of market-leading features and I’ll cover a few of them here.

The strap/body/glass combo seems to have nicely held up to lots of chlorinated pool sessions in a variety of pools of different lengths. I will add some thoughts later on Open Water Swimming soon – the lake has just opened aka “it’s still cold”.

You can just get in the pool and go with your watch. Or…..

For the more regimented swimmer you can follow workouts created on GARMIN CONNECT. Pool workouts have been possible for over a year.

Many sports watches that are also designed for swimming have some form of stroke detection. With the Fenix 3 & 920XT I initially found stroke detection somewhat hit and miss. But by 2016 Garmin had improved stroke detection to a VERY good level on the F3 and on the 920XT. Well at least it was for me. I’m a competent swimmer and my stroke still needs quite a bit of work yet the F3/920XT picked up all 3 (ahem) strokes VERY well.

Yet it seems to me that the F5 is not quite as good at stroke recognition. I’m getting a 90-95% hit rate of correct stroke length detection and that’s also in coached lane sessions, whereas with the 920XT I seemed to often get closer to 95-100%.

Added to that, it’s always a great game to see which of us in the lane got the closest total meterage to reality for the session. Usually there are 100s of metres of discrepancy between us all. There are always going to be some errors introduced by sharing a lane and drills but the F5 just feels a little less accurate to me. Perfectly usable though.

You can look at your summary stats in Garmin Connect or on the watch. Garmin Connect is a little limited in what it presents and could be improved to something like the POOL PLUGIN for sporttracks…which is pretty awesome.

Pool Plugin With HR Combined Files
Pool Plugin With HR from 920XT


Nevertheless, Garmin Connect is OK for a ‘quick look’ for those of you with a life outside of staring at your sports data (most of you hopefully 😉 ).

There are a few extra features for swimming. I particularly dislike the DRILL LOG. It’s a great way to enter a manual distance, for example to count kick sets where the F5’s wrist-based accelerometer would not produce correct distances. However the reason I dislike the DRILL LOG is because of my ineptitude and I usually have it drilling away as I am swimming normally. But that’s my fault. Garmin have changed how the DRILL LOG works from the 920XT and it is accessed and enabled when you have pressed LAP to pause a set rather than enabled/disabled as a general swim option – that was probably a good idea. Nice. I don’t seem to have messed up too much with that particular feature…yet!

There is a countdown timer and you can set manual pool length from approx. 17m to 150m, that should keep most people happy. And there are also a limited number of alerts that can be set based on time, distance or calories. I sometimes use the alerts to remind me to pay attention when I get to some infeasibly long point in my once weekly distance workout.

I couldn’t seem to find where the paused/lap screen layout could be changed and, yes, I WILL lose sleep over that tonight.

If you want HR whilst swimming then then you need to buy a Garmin HRM-TRI (Review) or HRM-SWIM. HR is cached in the chest strap and uploaded to the watch when you save the workout on your watch.

Some nice points:

  • The HRM-SWIM or HRM-TRI will give you the anaerobic/aerobic training effect feedback at the end of a SWIM session
  • You can manually force a download of HR data from a HRM-SWIM/Tri strap through the menus (exercise summary) if for some reason you pressed the wrong buttons or the cached HR data was not saved for some reason.



What’s missing in the water?

I’d say it’s a very good overall swim offering but, bearing in mind this is a premium product, I would criticise the F5 here

  • Better GPS location tagging. When I go to a public swimming lake I expect the Fenix to know what the lake is called and to record the lake name. When I go to a pool I expect the Fenix to get a quick GPS fix and tell me the pool name AND also automatically set the correct pool length. If you do a run-swim-run session you may well find your pool session GPS-tagged already, like this (red dot – below) so ‘all’ you need is a bit of firmware and a database linking location to pool size and name … simple (hmmm!).
Indoor pool mode WAS selected
  • already has similar GPS-related services – they have a nice Android app (probably iOS too).
  • I use the HRM-TRI for recording HR when lake swimming. Sometimes I use it for pool swimming and that normally is when I think I will not meet anyone who knows me as it looks a bit silly. Just for the avoidance of appearing silly, we need optical HR when swimming 😉 Don’t get me wrong, the HRM-TRI is an awesome piece of kit to add to the Fenix 5. indeed I’d probably recommend the HRM-TRI over the HRM-SWIM, the latter of which I find a bit uncomfortable due to its restricted elasticity. The HRM-SWIM might be better for super-serious (and fast) swimmers as it better adheres to an exposed chest whilst swimming/turning.
  • Optical HR needs to be sorted out & enabled for swimming. Polar already provide that on the low-end M200 and medium-range M600 and I found them both quite accurate. I suspect Garmin will enable oHR-SWIM later in 2017, if technically possible, using their existing ELEVATE sensor.
  • I would like a vibrational alert when ‘significant’ activity is detected AND whilst at the same time the watch is in the INTERVAL REST perio…ie when I have forgotten to press LAP a second time to start swimming.


Note: This section is based on my opinion for race suitability as I do not plan to use a Fenix 5 in a race. Although I have used the Fenix 5 for several multi-sport workouts. I used the Forerunner 935 for Ironman UK 2017.

There are two kinds of multi-sport mode; manual and pre-defined. For the manual one you press and hold the middle left button and change sport. You’re good to go and do the same thing again and again. It takes a few seconds each time but perfectly fine.

Garmin Fenix 5X 5 5S Forerunner 935 ReviewInstead, most of you might prefer a pre-defined multisport mode such as swim-run, duathlon or…the other one. I forget the name.

There is no triathlon mode as such. Really it’s a configurable and copyable multisport mode. It just so happens that one of the pre-configured multi-sport modes happens to be SWIM-BIKE-RUN ie triathlon!!

A Multisport mode puts together existing sport modes AND ALL THEIR properties. So If you have POOLSWIM as part of a multi-sport profile then, for example, the pool length is ALWAYS the same for the both. So if you set up your TRIATHLON profile well in advance of a race and then, perhaps, visit a different length pool in the interim you may have data issues on race day. I would strongly suggest a test run through your race-day profile if in-race stats are important to you.

The basic multi-sport profile has 5 segments and you can ADDITIONALLY have transitions.

Complex Multisport Workouts

With previous, recent Garmin multi-sport watches this led to the inability to perform complex and long brick workouts AND the inability to perform OTILLO SWIM-RUN type races without the judicious use of the LAP button. This has now been worked around by the addition of the MULTI-SPORT ‘REPEAT’ option which was added to the Fenix 3 in 2016. This simply ‘indefinitely loops’ your multisport profile. So TRIATHLON would go SWIM-BIKE-RUN-SWIM-BIKE-RUN-SWIM-….and so on forever.

There are a few anomalies here.

  1. ‘Transition 1’ will appear after every single repeated swim in the above example. Don’t worry about it.
  2. I don’t think it is possible to have a profile like this SWIM-BIKE-RUN-BIKE-RUN-BIKE-RUN…I used to do something like that on the 310XT (?) in the event of an incorrect lap button press in the heat of a race transition. But looping through all the 3 triathlon sports until you get to the right one is no big deal I suppose.
  3. There probably is a theoretical maximum number of REPEATS but I have no idea what it is nor any intention to test those heady heights of BRICKness.

There are also some feature-overrides that can be set at the multi-sport level. For example you can allow/deny; alerts, auto-scroll, auto-lap and auto-pause. You might also want to auto-lock the screens for each sport to avoid the occasional and inadvertent key press.

Multisport Omissions

The one thing you really can’t do, which is a little annoying, is press the LAP button to insert a manual lap in a particular sport within the multi-sport. This is because the lap button takes you to the next sport or transition.

Don’t forget AUTO-LAPS WILL WORK in multi-sport mode.

Another suggestion for Garmin would be a snappily-named “auto-sport-multisport” mode. I can’t count the number of times that I’m actually focussed on racing rather than gadgeting. Invariably I forget to press button for a variety of sensible reasons. The Fenix 5 automatically progressing to cycling once my power meter has hit the heady heights of 80w might be a good cue as might progressing to T1 once I start plodding on dry land rather than thrashing in the water. Something like that, or just a periodic vibrate alert of some sort might help for the first 5 minutes.

ironman-logo-iconIronman: Warning. Many sports watches give you battery lives that appear to exceed your intended race time. If you have backlight, GLONASS, alerts, live-tracking and everything else turned on you may well be lucky to get your watch to the end of a sprint tri (joking). But having your watch run out of juice half way through the marathon of an Ironman is NOT a joke. I can’t offer any specific guidance here other than BE CAUTIOUS in what you enable…give it some thought AND test if you can. See you in Bolton 2017! My suggestion is a low powered cycling mode on the Fenix + use a cycling head unit for real info. Edit: I had no battery issues at Ironman UK 2017.

Multisport omissions? – nope. It’s all good to go, I reckon.


How exciting a compass.

Garmin Fenix 5X 5 5S Forerunner 935 Review

Well, of course it’s a bit more than that! Yes, a bit more than the altimeter/barometer as well!

You can set the altitude of a specific POI. Voila when you at eat that POI a sneaky calibration to the EXACT altitude gets your Fenix off to a great elevational start. Clearly the obvious thing to do is set the elevation at your home – is the obviously named website for just this task.

As you can see on the Fenix 5X (only this model) you get a very nicely detailed OSM map. You can create and share OSM routes on Garmin Connect or in Garmin Base Camp. Alternatively, you can turn one of your previous excursions into a route or indeed you can turn a TCX, FIT or GPX file from someone else into a route. The precise mechanics of this is a bit of a dark art. I would tend to avoid Garmin Connect for route creation and err towards GPSIES.COM or, indeed, some of the other sports watch vendors websites are better at creating routes. You will, however, need to go via Garmin connect to synchronise the route. There are probably ways of just putting a GPX file in a folder on the Fenix 5 but that never seems to work for me on the rare occasions I create routes. I have wasted many frustrating hours of my life on route creation. Other than and fixing your files with Fit File repair Tool, I have no magical tip for you. Sorry!

Garmin Fenix 5X 5 5S Forerunner 935 Review




Garmin Fenix 5X 5 5S Forerunner 935 ReviewSteps Accuracy

This is a bit unscientific.

Walking a hundred steps several times and in several scenarios, I conclude that, for me, the Fenix 5 seems to UNDER-estimate the number of steps by 1-2%. I’m a slow walker and don’t swing my arms around too much if that helps.

1-2% is good enough for me.

Optical HR Accuracy

Many readers of this Garmin Fenix 5 review are new to optical HR and are keen to ascertain just how accurate it might be for them in many sporting scenarios.

I have some concerns with the optical HR accuracy on the Fenix 5, although I feel that generally, it is Ok. These comments are representative of the results I experienced:

  1. The optical HR is poor-to-Quite good when cycling outside but good when on a turbo trainer
  2. The optical HR is generally good-to-excellent for running outdoors
  3. Garmin do NOT enable optical HR when swimming, although it is possible to view it during a rest between sets ..secret 🙂
  4. When comparing nightly resting HR, the FIT file produced by Garmin Connect appears in the wrong format and was unusable for me.
  5. After visually comparing nightly resting HR data with QS EMFIT I would unscientifically say that the Fenix/EMFIT ‘just about agree’
Garmin Fenix 5X 5 5S Forerunner 935 Review
Forerunner 235, Fenix 5X, Suunto SPARTAN SPORT WHR

Firstly comparing to a Forerunner 235 (oHR) and Polar H10 on a Suunto SPARTAN ULTRA. I used the 235 in several scenarios to counter the argument, “Ah well, NO optical HR device would have done well in those circumstances“. In this case, clearly another one did. In fact they all worked very nicely indeed.


And here is another one from a trail run which is just about acceptable and you can assume that the ULTRA+H10 is ‘correct’.


And more of the same but this time with some intentional ‘stop-starts’ for Z1-Z3.

Finally let’s look at an extended Zone 2 run also with the SPARTAN SPORT WHR (Ultra with H10 and correct). This one warrants a double-sigh. Both the SPARTAN WHR and the F5X perform acceptably up to about 58 minutes when suddenly the WHR goes skyward and the F5X flops. Interestingly this coincided with a point of difficult GPS reception. The F5X is marginally better BUT there is absolutely no reason why either should suddenly go pear-shaped. MADNESS.

Garmin Fenix 5X 5 5S Forerunner 935 Review

However then we turn to cycling. This image shows a dire performance of the Fenix 5X’s oHR on a MTB on an easy trail. It’s compared to a Suunto SPARTAN SPORT WHR (optical) which performs very well.

And here is the same test repeated another day as I couldn’t believe it was so bad the first time. It’s maybe a little better for the 5X but still unusable, in my opinion.

Here is a slightly better cycling performance on a fairly smooth road. If you got this each time I’d say it was just about usable.

Garmin Fenix 5, 5X, 5s, 935 Review

And here we have an easy smooth ride with a few ‘normal’ stops and starts. Would you accept that? It’s borderline for me, admittedly only 20 minutes.

And here is the effect of a coffee stop, detracting from an otherwise good performance from the Fenix. Luckily I was fairly close to home on a short ride rather than half way through a 5 hour ride with a second half of oHR data-nonsense to possibly look forward to.

Garmin Fenix 5, 5X, 5s, 935 Review


So if you want to use this in triathlons/cycling then you have a bit of a dilemma as you will HAVE to use a chest strap to get reliably accurate HR results. The problem I have here is the integrity of the cost model from Garmin. YOU are being asked to pay a premium price for a premium model. You also have no choice but to pay for non-optional, optical HR which probably adds $/£50-$/£80 to the price. BUT now I am telling you that you also need to go and buy a HRM-TRI chest strap for over £50 (Don’t forget to add that to the footpod you’ll need to buy as well).

Nice work if you can get it, we’re both in the wrong business you and me. Charge more for a key, but unfinished, non-optional feature and then get the customer to pay even more to work around it. That certainly wouldn’t wash in my ‘other business’. It REALLY wouldn’t. And, to be honest, I’d be too embarrassed to charge a premium price to my customers in such circumstances.

YOU might get lucky of course. Optical HR performance varies from person-to-person. But I’ve shown you a scenario, above, where another (Suunto) oHR device performs well but the Fenix 5 did not. So don’t blame yourself if oHR doesn’t work for you it could simply be the technology.

FORUMS: I find it surprising that the majority of people appear happy with the degree of inaccuracy delivered by the Fenix 5. This is evidenced on Garmin’s forums where there are many more complaints about GPS inaccuracy than oHR inaccuracy. I do use HR data a lot so I am probably biased in that respect or maybe I’m just the only person with problems?

SOLUTION: Garmin should only enable optical HR in the sports profiles where it works adequately – perhaps already why Garmin don’t enable it in SWIM mode I suppose.

WORKAROUNDS: (This) article suggests some of the ways to get your optical HR device to work better.

Summary: optical HR for running is OK. That’s about it.


Garmin Fenix 5X 5 5S Forerunner 935 Review
M200 Blue, Fenix 5X Red

The GPS accuracy is certainly usable. You’ll more likely find it does the job unless you have a very specific interest in tracking your exact positions and speeds. Lots of you do have precisely that interest, of course.

In my opinion, nearly all the main, modern sports watches do a good enough job in their GPS accuracy. But when you have specific needs for accurate speeds/paces or for navigational accuracy then you want great accuracy. But wait a minute. That is surely precisely why you are looking to buy a top-end device?

I conduct a formal test and the files and analysis are available (here and here) if you want to look. I re-test in fairly controlled conditions over time and take the best result. The Suunto SPARTAN SPORTs are consistently the best however the absolute best wrist watch result was from the Polar M200!

The M200 is shown in blue on the right. This is the hardest part of the test and the M200 almost gets it. The red line is the Fenix 5X at 4 or 5 times the price. Admittedly the Fenix 5X has not yet been tested by me with GLONASS on. Although with other watches I have found that GLONASS does not seem to improve performance and indeed often makes it worse.

The F5X scored 69% which sounds low but I say 70% is good. The F5X scored quite well on EASY, MEDIUM and HARD sections but just not as well as other watches. So it scored a shrug of the shoulders and an ‘OK’. Very uninspiring.

NOTE WELL: General feedback is that the 935 has better GPS accuracy than the Fenix 5X. I have not tested the 935 for GPS accuracy as yet. (Edit: Yes the 935 is better, I tested it)

I also, of course, look at other GPS tracks on a more ad-hoc basis. Pretty much every workout I did with the Fenix I had another watch or two at the same time. You may have seen this earlier satellite image in the optical HR section with a corner shown comparing to an Edge 820 and a Suunto SPARTAN WHR. The Fenix 5 is ‘alright’ but just doesn’t quite cut the mustard that the SPARTAN slices through with a sabre.

If you can think of another phrase that describes OKness, or mediocrity or ‘it’ll do’ then that will describe the Fenix 5’s GPS performance.

Sorry, that’s what I found. Again and again, almost every time.


This Garmin Fenix 5 review now looks in a bit more detail at the accuracy of the 5X with mapping. The 5X has a full routing engine built in.

Garmin Fenix 5X 5 5S Forerunner 935 Review

Navigational accuracy is closely linked to GPS accuracy as the Fenix needs to know where you are. It also needs to know where you are going AND how to get you there in a reasonable manner. Garmin, TomTom and Co have been doing this well for years in our car Satnavs.

This section only concerns the Fenix 5X. The other models will let you follow a ‘line trail’ made from a tcx/gpx/fit file but the F5X has full-blown OSM maps that include the ability to ‘understand’ MANY trails as well as roads. ie it can route you over a trail. Cool !!

Garmin Fenix 5 review 5X 5 5S Forerunner 935 Review
Part of the Bushy Park parkrun course

Navigating in easy scenarios

I have been showing all my friends the wonderful maps on my watch. Nearly all were pretty amazed. They really are fully detailed to a good level of resolution. The watch format and screen are a little small for some eyes but ‘it is what it is‘ and would probably look a little ridiculous if any larger. Anyway, at the local fete we all played around with the map and could easily get ourselves to different parts of the park. I was very excited. Navigation 101 was passed with flying colours. Ok the screen was sometimes a little slow to appear but I thought the F5X would dispel the periodic navigational awfulness of the Edge 820 that I use fairly regularly for navigating new cycling routes.

Wrong. The Fenix 5X was worse.

The state of navigation

Garmin Fenix 5X 5 5S Forerunner 935 Review
Hot key to save POI

A summary of my experience here suggests that as MAPS are a new feature to the Fenix range then this particular feature-set has not yet passed beta testing. It can’t have. All the glowing reviews on the internet simply cannot have tested navigation for more than a walk in the park with the kids. ie the Navigation 101. The bit I did first. Within the space of 60 minutes of run-navigating I had so many problems that I can could see little point in doing any further MAP-based route tests either for hiking, running (some more) or cycling on this firmware version. (v3.30, GPS v4.30). What should have taken me 50 easy minutes actually took me well over an hour and I got lost – well, I knew where I was but the watch couldn’t direct me on the route.





Navigation in practice

I created a relatively simple 10k route on a flat and generally open park. The route took in some clumps of trees and lines of trees. I used GPS and not GLONASS. Relatively easy stuff. Check out the section on GLONASS accuracy if you think I should have turned that on!

  1. With a full GPS lock for the previous 5 minutes and at an ‘open air’ start I loaded the course. The F5X took more than 1km of running slowly at 5:15/km to even correctly mark my position on the map. It was going wildly off course and indicating that I was on nearby roads 30m away rather than on the trail that the GPS route and me both really followed. Strange. After 1km it found me. Hmmm
  2. At other times I deliberately went off course. The F5X took between 21 and 26m to realise that I was off course and to throw up the ‘Off Course’ alert. If you are hiking that’s probably Ok, it’s nowhere near OK enough for me when running.
  3. At another point I deliberately ran 10m parallel to the correct route. It did not spot this and showed me being on the correct route. I note that GPS accuracy should be ‘to 5m’
  4. Going into the ZOOM mode on the map is fraught with danger. Zooming in/out can cause the device to temporarily freeze and/or slow down. It looks like either bad coding or underspecified hardware.
  5. At other times half of the screen would not draw at all. The only fix was to reload the course.
  6. At other times when I completely stopped running the 5X must have had some algorithm where it assumed I was continuing in the same direction at the same speed (and this was nowhere near a tree).
  7. Generally the map seemed to show my position as being 5m behind where I actually was. This is probably expected behaviour due to GPS accuracy. It would be fine for hiking and that was probably OK for the speed I was running at but if there was any sense of urgency in my routing coupled with a higher speed I can’t see it being that useful.
  8. With oHR then there is only one recommended way to wear the watch (ie normally and not reversed). Consequently it is a little awkward to twist your arm to periodically view the map and your position whilst running.
  9. On a different occasion at another point away from the start of the course I loaded the course. I would expect to be prompted to be navigated to the start like on other Garmin. I wasn’t.
Garmin Fenix 5X 5 5S Forerunner 935 Review
Maybe half the screen area of a small-sized navigational bike computer?

The officials at World Orienteering events can breathe a huge sigh of relief, the F5X is not going to help people cheat on this firmware version.

This Epic Fail somewhat curtailed my keenness to do any other ‘testing’ as clearly Garmin haven’t bothered to do any testing on these features so why should I? In my experience and my opinion the functionality here is so poor that it would justify returning the unit. As it stands it’s ‘not fit for purpose’. Again, I stress that this is in my experience. You may have better luck. Indeed every other review I’ve read does not seem to have encountered any problems in this area with their free PR watches. Strange that.

No doubt some people will think I’m making this up. No doubt Garmin will sell a million F5 units like they have for the F3. So I must be wrong. I can only report what I found.


GLONASS is supposed to increase the chance of obtaining 4.5/5m levels of positional accuracy when working alongside GPS. I often find that GLONASS can make matters worse as well as eating more battery. I have only done one test with the F5X and GLONASS and it was so bad that I won’t waste my time doing any more on this firmware version. This is from my standard test route except I did it on a MTB going slowly with GPS+GLONASS on, the file and analysis are available (here and here).

The Fenix 5X scored the second WORST result ever. The absolute worst was from my Huawei smartphone, admittedly the Huawei was considerably worse. The Fenix 5X was the first sports watch to score ‘0’ on any of the sections of my test…ever. This is the worst (and hardest) part of the test where a whole 0.5km is omitted after a tunnel is encountered. Indeed tunnels and trees may have been a factor elsewhere. That’s why you need a hard test route…

Garmin Fenix 5X 5 5S Forerunner 935 Review
5X Green with GLONASS


TOP TIP: Do NOT enable GLONASS on the Fenix 5X.

On the 5, 5s and 935 GLONASS was NOT  as bad as on the 5X.



This section of the Garmin Fenix 5 review (accuracy) is not too important to most readers and is included for completeness.

The following chart shows the elevation drift on a Fenix 5 over a trail ride – this is about as mountainous as my rides usually get, sorry! The Fenix 5 starts to drift after 1 hour and then more noticeably after 2-3 hours. My 5X wouldn’t start that day and so I used someone else’s Fenix 5 data for the same route. The blue track is ‘correct’ and based on SRTM data of the actual route taken. The Fenix 5 clearly drifts over time, presumably at least due to changes in air pressure. It looks like being short by 25% much of the time. Personally I would have little use for that although relative ascents/descents over short periods should still be OK.

You would have thought that some degree of in-ride/dynamic, GPS-based, periodic altitude re-calibration could stop this happening to this degree? Perhaps only recalibrating based on GPS when a certain level of confidence in a new elevation was determined?

You could probably recalibrate every hour. I know I wouldn’t.

If I were to show the other data from the Edge 820 (partial ride data) or the Lezyne (rubbish elevation data), it wouldn’t really help the understanding so I removed it from this chart.

There are lots of people with altimetry issues: see this link on the forums.

CIQ Apps and other bits

Garmin’s Connect IQ or CIQ is their app store. Most things there are free but this is starting to change.


Garmin Fenix 5X 5 5S Forerunner 935 Review

You will probably look at CIQ for an alternative watch face. If you buy extra sensors like STRYD then you might find their app useful. An app contains more functionality for the Fenix. Indeed some of the pre-packaged functionalities of the Fenix are really apps developed by Garmin. For my own personal use I find DATA FIELDS the most useful; these display and can record non-standard data into a FIT file. For example, a STRYD data field can be placed on ANY regular screen and will show you a particular flavour of running power. It will then save the raw power into the FIT file and you can see that data in Garmin Connect.

Something like the following chart from Garmin Connect shows POWER, LSS and Form Power from STRYD – the same/similar data could instead have been captured with the STRYD CIQ app:

stryd metrics in garmin connect



Sensor support is market-leading and generally excellent in its implementation. Specifically Garmin have a ‘sensor pool’ meaning that you can have several sensors of the same time ‘registered’ on the Fenix 5. Although only one pairing will usually be active for each sensor type

In terms of the types of sensor supported, there are one notable omission that I can think of :

  1. Running power sensor (STRYD)

It really is a case of ‘Camera, lights, action…” VIRB cameras are supported, Varia/Bontrager lights are supported and all the sensors for your sporting action too.

“Nonsense,” you say! Garmin only supports ANT+.

Garmin Fenix 5X 5 5S Forerunner 935 Review

Nope!! Bluetooth SMART are now supported too.

  • Heart Rate Chest strap – from your ancient Garmin ANT+ hard strap to my new Bluetooth Polar H10, all is sweet and dandy. You will only get HR from these and most of the straps will also be accurate to HRV levels too (HRV not tested). ‘Special’ features from straps will NOT work natively unless they are from Garmin. eg caching WILL work with the Garmin HRM-TRI but not with the Polar H10’s caching or with Suunto SMART Belt’s caching. Expect issues if you try to do unusual things with dual-band straps like a WAHOO TICKR-X or 4iiii Viiiiva strap…just use ANT+. To reiterate once again, if you intend to take cycling, swimming and/or triathlon HR data seriously then you will buy a Garmin HRM-TRI which will give you caching, accuracy, running dynamics AND awesomeness.
  • Bike speed and/or cadence sensors – yep, both Bluetooth and ANT+ versions are supported. As an improving cyclist, a wise investment is a bike cadence sensor. I would personally go for the cadence-only sensor rather than the GSC10- speed+cadence sensor.
  • Running Footpods – both ANT+ and Bluetooth are supported. A running footpod is necessary to get proper running speed and, often, proper running cadence. The Fenix 5 GPS speed is mostly wrong and anything from the internal accelerometer is also fraught with wrongness. I got Polar’s STRIDE SENSOR to pair but there seemed to be some outdoor speed calibration issues (??). Buy a Garmin one. If you want a properly accurate footpod then buy a STRYD (expensive).
  • Running Dynamics pod – ANT+ only, from Garmin. Why? Why? Why? (A: you want running dynamics but don’t want a chest strap)
  • Bike Power Meter – ANT+ and Bluetooth are both supported. All ANT+ power meters should work and many also give cadence as well as power. Bluetooth power meters should be checked for compatibility first. Cycling Dynamics metrics are also supported through ANT+ from Garmin, BePro and other PM vendors.
  • Running Power Meter – the only one is STRYD which will communicate to the Fenix 5 with ANT+ perfectly well but there is no pre-installed/native support for it (not a problem tho)
  • Muscle Oxygen – This was a surprise inclusion with pre-installed/native ANT+ support for MOXY and BSX. Super cool.
  • Other specialist, supported ANT+ sensors include: Camera (VIRB); gear shifting (Di2, SRAM RED, Campagnolo); external temperature (TEMPE – more accurate than the internal sensor); heads-up-display (Varia vision); lights (Garmin, Bontrager); Radar (Garmin Varia);

WARNING (14 April 2018) – There are STILL reports of ANT+ sensor dropouts on the Fenix 5 and Fenix 5S with several sensor brands including STAGES & STRYD. Check the Garmin forums (here) for the latest status. My understanding is that the Fenix 5 PLUS range (new hardware) will rectify these problems. My further belief is that now Garmin are selling slightly modified hardware as a firmware fix was not possible – so change your watch if you have an old one.


I’ll start off this section of the Garmin Fenix 5 Review by showing you some new personal physiology screens and some screens that will be familiar to previous Garmin owners.

Garmin partner with FIRSTBEAT in the area of physiological metrics. FIRSTBEAT are probably the leaders in this field and also supply their algorithms and expertise to other companies such as JABRA, SUUNTO, SAMSUNG and HUAWEI – here is FIRSTBEAT’s site. Polar are good on this too.

Another prism to look through is which ones can be used for ANY activity and which ones are specific to running or cycling.

There is a VO2max for both running and cycling. You should probably be able to get your into the high 50s or low to mid 60s with some work over time. Age plays a part along with genetics but VO2max is the ‘gold standard measure of your ‘fitness’ at a given point in time. If measured correctly, then you will only notice relatively modest improvements over the weeks.

It is a great indicator of improvement once your Fenix starts fine-tuning its interpretation of your exercises. Don’t get too excited though. You and I could both have the same VO2max yet if you were the world’s most biomechanically efficient runner and I the worst then you would be considerably faster than me. – general info

Your “Training Load” is assessed in light of the estimated VO2max to produce your “Training Status,” which is a description of how your training efforts are going – productive, unproductive, peaking, detraining, etc.. These are useful to know as you move through the cycles of your training plan so you can compare what your device is saying to what the plan should be delivering for you.

Whilst I frequently admire FIRSTBEAT’s work I can’t help wondering how well the algorithms will work if there is either incomplete HR data (ie omitted because of swimming) or if the oHR data is inaccurate.

Lactate Threshold Heart Rates (LTHR) represent a physiological turning point in how your body is responding to exercise. It’s a complicated area but the LTHR is, in my opinion, a much better place to set HR training Zones from rather than HRmax based on your age. Training can make your LTHR go higher. Endurance athletes definitely DO want to achieve that eg one benefit of an increased LTHR would be an improved ability to use fat (rather than limited carbs) as a fuel source at a given level of effort. – general info

The Training Effect of your workout now has anaerobic and aerobic components. Again this is a complicated area but the effect you want to achieve from training will, for example, depend on the stage of your training and your race duration. Further from your race you would want aerobic effects as they remain in your body longer. For shorter distance races and as you close in on your race then so the amount of desired anaerobic effect would increase. – general info

Finally the ‘Recovery Hours’ are a useful guide to when your next hard session would be. After one hard session it’s likely you will be told to wait 2 or 3 more days before the next HARD session. Again, it’s a complicated area but this is generally good guidance to at least consider.

Some of these metrics will require you to use a chest strap at some point and some will require a power meter (cycling). If you want to get more serious about your training you would have those two anyway. If not, don’t worry.


This Garmin Fenix 5 review has covered most of the key areas of functionality for most athletes and has given you a good indication of the accuracy of the various components.

The Garmin Fenix 5 is clearly a contender for the best multisport watch. The Garmin Forerunner 935 is also a contender for the best triathlon watch and perhaps even a contender for the best running watch.


The Fenix/935 series is the most-featured set of sports watches ever made.

Looking back 5, 6 or more years, the improvements in features NOW are staggering compared to what was then on offer. The detail of the Fenix’s functional enhancements are everywhere in its rich menus; as an example just look at the history log of your exercises and you get a map of your workout, heart rate charts and time-in-zones. A few years ago you would have been lucky to get summary information for your laps.

It is also very likely that the Fenix 5/935 will keep on getting feature-improvements from Garmin at least until 2019. For example, Autumn/Fall 2017 will see the introduction of Garmin Running Power.

I also have to admire the delivery of different hardware variants to suit different tastes as well as a market-leading battery.


So where’s the catch?

Unfortunately, there are catches and they are not trivial. Here they are:

  • ANT+ pairing hardware faults – The Fenix 5 and Fenix 5S have hardware ‘issues’ that cause certain users to experience multiple ANT+ signal dropouts. I understand that this CANNOT be fixed by firmware. A new “Fenix 5 PLUS” range of Fenix 5 watches will be released in Q4.2017/Q1.2018 to rectify this. If you currently experience these problems…send it back.
  • Cost – eye-watering, purse/wallet-emptying
  • Under-specified hardware – maps are slow to load/zoom on the 5X and the screen resolution on the entire range is too low for a 24×7 watch but perfectly fine for a sports-only watch.
  • I would nit-pick to politely request Garmin to include the notable feature omissions of native running power support and optical HR when swimming to keep up with aspects of Polar and Suunto’s competitive offerings. Note even with the Q4.2017 release of Garmin Running Power this will NOT include native running power support.
  • GPS – GPS performance is “OK” and really that ‘OK’ level of performance is not good enough at this price point BUT it is likely Garmin will work to improve that through firmware releases. To be clear: in my experience, there ARE more accurate GPS alternatives from Suunto and Polar.
  • Optical HR – the Fenix 5/935’s optical HR accuracy, in my experience, is worse than I found on previous Garmin watches using similar ELEVATE technology. Indeed I would say the oHR is only acceptable for running and, coupled with the swimming oHR omission, makes the oHR entirely redundant for triathlon. Others have had different experiences to me; others have had similar experiences to me. You might be lucky. Or not. Again Garmin will be working on improving this.
  • Whilst the 935 variant of the Fenix 5 is designed for triathlon, in my opinion, the round watch face is not so well designed for triathlon. Some of you will disagree. Some will agree.
  • Navigation whilst running and following a course bordered on unusable.
  • Elevation accuracy over extended time periods seems somewhat suspect.

Remember, as I said at the start, this review is intentionally biased to be negative-leaning to provide you with an alternative viewpoint to the consensus. The consensus worry about their next loan item from Garmin..I buy ALL my Garmin free PR watches here. I want to please YOU, not Garmin. The Fenix 5 is a phenomenal piece of kit though!

  • The 5 PLUS series of Fenix watches is better. More functionality AND some of the above accuracy/connectivity problems resolved.


Q: Would the5krunner buy this or recommend this watch?

A: I clearly have bought it/them.

As ‘me the triathlete’ rather than as ‘me the the5krunner’, I can see no reason to upgrade from my ugly but highly functional Forerunner 920XT – edit: but I did !!. I would specifically point out that the Fenix 5S and the Fenix 5 models have hardware issues with connectivity to certain ANT+ sensors and these issues CANNOT be fixed by firmware.  I would definately recommend the Forerunner 935 + STRYD + HRM-TRI combination to triathletes and I would definitely recommend the Fenix 5S Plus to people with smaller wrists and who might also be triathletes.


Garmin Fenix 5X


Garmin Forerunner 935
Best REI/Wiggle/PMC price is linked to. Prices are about Eur450/$420/£430 and will stay around that level until Summer 2019. .

There is 10% off most stuff at Power Meter City with the coupon / discount / promo code: the5krunner10. HOWEVER It will not work for the Forerunner 935/Fenix 5. Sorry – there is a 10% store credit instead for Garmin products. That will be at list-price everywhere for some time, plus Garmin sternly frown upon discounting in any case while products are under MAP.



power meter city
Fenix 5 at PMC – 10% Store Credit

Garmin Fenix 5
Best REI/Wiggle/PMC price is linked to. Prices are about Eur480/$420/£430 and will stay around that level until 2019. .

Garmin Fenix 5X
Best REI/Wiggle/PMC price is linked to. Prices are about Eur700/$620/£530 and will stay around that level until 2019 but sale prices will come and go. .

Garmin Fenix 5S
Best REI/Wiggle/PMC price is linked to. Prices are about Eur495/$550/£425 and will stay around that level until 2019 but sale prices will come and go. .

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35 thoughts on “Garmin Fenix 5 Review including | 5x | 5s | Forerunner 935 |

  1. Thanks for this good review. I think I will keep my Polar V800 and wait for the upgrade of teh V800 later on this year.

      1. too bad but for your review you would absoultely deserve a commision, great job! i like your reviews more than DCRs, DCR is faster but yours are better focused on training goals and not only functionality.

        I´m still undecided what watch to get next, 935 or spartan or waiting for a v800 successor… (hopefully soon)

  2. A Seriously Great Review! Looks like you have convinced me to NOT upgrade my ancient 310xt though, as who would want lower GPS accuracy from such an expensive watch? Besides running and cycling I also need it to be accurate while hiking, and maybe I should just buy the new Casio WSDF20 with Viewranger integration and save my 310xt for running? Or wait for Garmin to address these deal killing issues?!

    1. i’m scouring ebay (seriously) right now for a 305. I always remember it as being great but I want to see if the good old days really were good. the f5 might just have one or two more features.

      1. I still have a FR610… GPS fix takes usually longer compared to watch with working/valid ‘EPO.bin’. But the tracking itself is very good. Still amazed how well this watch tracks the path – compared to newer models.

  3. Thanks for the review. Good detail on the FirstBeat 2.0 features, you may also want to note that with a “variable” oHR FB 2.0’s value might be reduced…Also the FR935 is a very different animal when it comes to GPS performance, i.e. a lot better than the F5, as seen with the multiple feedback from those who switched from the F5 to the FR935.

      1. I was more curious about the number of days between recharges x your daily use? Better than Garmin spec?

    1. i’ve heard reports that battery life may be better than the spec. I charge mine relatively regularly out of habit so I don’t really see any issues that I can point to. the %age figure often ‘seems’ lower than I would expect indicating poss higher battery consumption but I am far from sure. conversely my charger is low powered so it could be a charign issue coupled with an issue of poor charging fro the dodgy charging cable/socket.

      1. For the record, since I am now using for more than a month. Using GPS takes about 6%/hour from battery and daily use only around 3 to 4%/day. Since my run workouts are mostly on treadmill these days (which drains 1 to 2% at most with oHR 1-sec recording), I am going to 3 weeks without having to recharge and still have 14% left. Way better than I expected!

      2. Just did 😀

        24 days 11 hours!

        To be more exact, the battery was already showing 0% but watch was still working. From the knowledge I got from last time (n = 1, ok, but more than enough for me), it would ran out in a couple

        oHR working 24×7
        bluetooth off, except when necessary to sync (used more WiFi lately)
        10h 20min running on Treadmill (no GPS), using oHR
        1h 02min running outside using GPS, using Polar H10
        Stryd data fields used on all workouts
        Some workouts used RideDataPlus to try (don´t think it would change much, but just for the full record)

        Again, much better than I expected. I know running outside would drain at a faster race, but this is not an option for me at the moment (I wish I could), so at least I don´t need to recharge more often.

  4. Did you ultimately keep the 5X? It’s big, and heavier than the 5, but I do like the full color, and topo maps for when I go hiking.

    Yesterday, I was running and noticed the 5X had a bit of “bounce” on my 6 2/3 in. circumference wrists, even though the band was on snug/tight – especially as I started to go faster and sweat. It got me concerned about OHR issues you mentioned.

  5. The 5X is a great hiking watch (specifically because of the maps).

    I’m wondering your thoughts on if the 5X will be a great (albeit heavy) all-purpose watch, for triathlon sports, as well. If not, I can return the 5X and use my phone (Gaia app) for hiking nav, then buy a lighter weight, longer battery life Fenix 5 or 935 for triathlon sports.

  6. BTW… “However this review will dwell a little on the more negative aspects of …
    However out of respect for you wanting to do your research properly I’ll try, at times, to present a counter argument to the prevailing wisdom. … “So…. it’s GREAT and yet you’re going to be negative???” Yes I am, a little, but I can also draw your attention to … but, hey, at least I tried to do the right thing.

    This (being little “negative”) is something I really really appreciate about you reviews. And of course the ~massive~ pinch of salt. ?

    1. SportTracks (desktop version, not for free), Excel (not for free) or Google Sheets, GoldenCheetah… but the best is DCR’s Analyzer (not for free).

  7. Did you test the Forerunner 935’s elevation accuracy as well? Did it exhibit the same drift as the Fenix 5?

    1. For our both FR935 I can say… no drift compared to F3, F3HR or E1K. But all devices have different elevation at point of start.

      1. Thanks guys, sounds all good! Tempted to buy the 935. Not sure if I should wait for a 745 or 645…

  8. The Garmins are becoming cheaper now, especially the older Fenix 5 now that the Plus is out.

    Reading these reviews I wish I’d looked at the Suunto, having found with the very twisty routes of orienteering in difficult GPS locations that the 935 is a little all over the place. It gets the rough shape of my route but not the precision. To be fair, the rough shape is enough to compare notes with other runners after the race. “I went this way here”.

    It does mean that if I say “I navigated it in 7.3km” then that 7.3km could be out by a reasonable margin. Yet when comparing navigation efficiency in an event like an urban where terrain is always good then that distance is quite useful.

    1. yep a suunto an a polar might be slightly better. i would have thought a footpod will help with the overall distance i think STRYD also includes more correct calcs when you are walking

  9. So with the new Suunto 9 Baro out – how would you compare the two in terms of GPS and altimeter accuracy?
    Would you choose the 935 or the Suunto 9 Baro between the two of them?

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