2012: Definitive Garmin Forerunner 305 REVIEW for 5k, duathlon and triathlon

Garmin Forerunner 305
Forerunner 305 (December 2011) – now discontinued

Summary: It is a serious entry-level GPS training/racing watch with heart rate monitor. It is one of the best priced units for the features. It’s near perfect for 5k training and racing your 5k parkruns. With a few extra bits it is nearly perfect for duathlon training and racing. For triathlon (well swimming) there are training and racing limitations. It’s good enough to support you getting below 15 minutes in your 5k and an Age Group Duathlon World Championship medal.

The acid test: Would I buy another. Yes! And I have. And I have recommended it to friends who have bought one. It is one of my family!

Is it perfect? No. Then again, neither am I. But it may well be perfect for your needs…

Out of the box what do you get? The Forerunner 305 unit. A HR strap, an alternate short wrist strap (with tool), a USB cradle for PC/MAC connectivity and charging, Software and a box. That is all you need to start.

What don’t you get?

  1. A footpod to measure footfall/running cadence or that can be used on an indoor trainer. You can buy one. (here=> Garmin 010-10998-00 and 010-11092-00)
  2. A bike cadence (pedalling/speed) sensor for on-road cadence, turbo trainer cadence and turbo trainer speed. You can buy one (click this=>Garmin GSC 10)
  3. Premium soft HRM strap. You can buy one.
  4. Bike mount kit. You can buy one. May not fit if you have aero bars.
  5. Quick release/fabric strap. You can buy one.
  6. Bike power unit. You can’t buy one. There are clever ways of converting speed to power on turbo trainers and displaying real-time TRAINING stats – I’ll come back to that!
  7. Waterproof swim cover. You can buy one.
  8. Wireless ANT+ Dongle for PC connectivity. You can buy one.

I’ve just bought it what do I need to do?

  1. Charge it up. Either connect it to your PC or plug it into the mains.
  2. Set your region, time zone and units (imperial/metric)
  3. Tell it what accessories you have.
  4. Turn it on and get going!

How can I customise it for me?

  1. Display settings can be changed for each individual sport. So I use cycling speed in KMH and running PACE PER KM. For swimming I use it as a lap timer/counter. You can have up to 4 exercise metrics/parameters per sport – fully customisable. So in run training I have current pace, lap or interval pace, HR and total time. You can also scroll from one screen to another screen with different metrics for the SAME sport (if you really want to).
  2. You can set your own training and racing zones. For HR based training you will need to research LTHR and then enter your own zones based on this. You can set climb zones, speed zones, cadence zones and pace zones.
  3. You can set alerts for if you go too fast, or if your heart goes too high/low, or if you pedal too slow and so on.
  4. You can change how long the light stays on for! And more!

Using it There’s a start/stop button which does what it says. There’s a lap button which does what it says. It also advances you to the next interval or to the end of the current auto lap. Press the ‘on/off’ button during use and the light comes on. Press and hold ‘lap’ after finishing and the exercise is properly stopped (you should do this every time) Press and hold ‘mode’ before starting and you can switch between indoor/outdoor use and between exercise types without having to do that through the menus. Why not save one of your 5k parkruns as a ‘course’ you can then run against it next time to beat your PB. Or if you are pacing you will know with certainty how well you are doing. Is it accurate? Yes. Accurate enough. Just run 5k that it shows as 5020m? Well that’s probably you not going in a straight line rather than the watch! There’s also of course lots of other stuff which you can discover by yourself ranging from how long the light stays on for to getting it to beep to tell you to go faster.

Analysing it The bundled Garmin Training Centre software is rubbish. Except using it for the management of the unit and your exercises. Use SportTracks V3 for ALL ANALYSIS – look at the plugins for specialist stuff telling you what gear you were in, what an estimate of your cycling power was or how well your taper is doing. It’s all there – some of it minimally priced. None of the extras are expensive. Much of it is also useful for high level athletes as well as you and I. Try also Garmin Connect or Training Peaks.

The downsides:

  1. It’s too big…or is it? It is big BUT you can actually read the display (which helps!) And it is not heavy.
  2. Battery life is OK for what you will use it for. BUT you should charge after every use. If you do very, very long sessions then you can change the frequency of data recording but that will apply to very few of you. It was fine for a 100 mile cycle ride I did recently for example.
  3. The time taken to pick up a GPS signal deteriorates over time of ownership. I don’t know why. With the latest firmware updates from the Garmin website installed all you need to do is a hard reset (basically a ctrl-alt-delete, see below).
  4. Once a year mine has gone wrong. You press the on button and it doesn’t go on.
    1. Soft reset: with the unit off press and hold ‘lap’ and ‘mode’ simultaneously for 3 secs and then let go. It may start-up.
    2. Hard reset. Do a soft reset but then also at the same time with a third finger press the on button for the 3 secs. Let go and it should turn on. You might lose data on the watch. Beats buying a new watch.
    3. No volume control.
    4. Many of the watch’s setting can be set by using Garmin Training Centre (free software that comes with your device). Use that software for exercise creation and  changing personal settings, this also makes a backup of all your data and personal settings. (Well most of them)
    5. No power/wattage for the road. You can’t wear it on your wrist for a swim.

OK I want to get a bit more serious. How do I set up complex training sessions? You CAN do this on the watch. BUT it will be incredibly time-consuming so don’t bother. Use Garmin Training Centre. You will be able to create complex interval sessions based on almost any training variable you would ever need to: HR, speed, pace, cadence etc.

What about multi-sport then? Yep you are OK here as well. The 305 has a multi-sport mode. When you press the ‘lap’ key it moves on to the next ‘session’. That session can be either a transition period or a new sport or the same sport. So, for example, I use it for a hard duathlon/triathlon brick comprising run, transition, bike, transition, run, transition, bike, transition, run, transition … you get the picture! Far more than just swim/bike/run. NOTE: Always test out multi-sport mode if you’ve made any changes before you race. Just like buying a new bit of bike kit. Always use it/try it out before you race.

And Triathlon? The watch does work in water. **Note the limitations on the Garmin website**.  But when worn on your wrist I suspect it would soon leak. So, buy a waterproof bag (Ziplock) and stick it in your swimming cap. It does pick up HR in water. But it’s not great. There will be gaps in your data. The sharp-eyed amongst you will have realised that this makes the watch OK for training but in a triathlon race it will not be realistically usable in the swim in your cap. Then again if you are racing will you really be looking at your watch whilst racing the swim section? I suspect not. So all you lose is the metrics of the race for analysing later.

Duathlon Problems? It would not be possible to fit this device to my handlebars with the bike kit because of the tri bars. So I wear the watch with the display on the underside of my wrist. Realistically this is what you should do anyway as you do not want the extra task of taking a watch from your handle bars and putting on your wrist in a race…one more thing to go wrong and /or forget.

Running Problems? Er no, Not really.

Summary again but shorter: Perfect for ANY runner, parkrunners, Age Group Duathletes and, with caveats, triathletes.

Price Comparison

Watches Comparison July 7th 2015AmazonUKAmazon2USA
Adidas MiCoach Smart Run£209.99Link$188.00Link
BRYTON 60H / S430£174.90Link$199.00Link
Epson SF-810£201.08Link$506.06Link
Epson SF-710£151.14Link$297.91Link
Epson SF-510£140.63Link$269.10Link
Epson SF-310£109.99Link$208.11Link
Fitbit Charge HR£105.00Link$149.95Link
Garmin Edge 1000£390.84Link$599.99Link
Garmin Edge 520TBCTBC
Garmin Edge 510£249.36Link$304.95Link
Garmin Edge 810£223.33Link$394.95Link
Garmin Edge 25£139.99Link$169.99Link
Garmin Edge 20£109.99Link$129.99Link
Garmin Epix£344.45Link$549.99Link
Garmin Fenix3 (Sapphire)£385.00Link$589.95Link
Garmin Forerunner 220£158.09Link$236.99Link
Garmin Forerunner 620£248.24Link$388.28Link
Garmin Forerunner 630TBC
Garmin 910 XT£232.49Link$318.11Link
Garmin 920 XT£302.65Link$483.00Link
Garmin VivoActive£199.10Link$244.95Link
Mio Alpha 2£117.71Link$199.00Link
Nike+ SportWatch£179.99Link$149.89Link
Polar M400£119.95Link$229.95Link
Polar V800£266.95Link$308.49Link
Suunto Ambit 3 PEAK£277.51Link$381.10Link
Suunto Ambit 3 Sport£194.95Link$319.95Link
Suunto Ambit 2R£151.64Link$167.16Link
TomTom MultiSport£148.58Link$148.44Link
TomTom MultiSport Cardio£179.99Link$246.99Link
TomTom Runner£89.99Link$99.99Link
TomTom Runner Cardio£161.99Link$199.99Link



Reader-Powered Content

This content is not sponsored. It’s mostly me behind the labour of love which is this site and I appreciate everyone who follows, subscribes or Buys Me A Coffee ❤️ Alternatively please buy the reviewed product from my partners. Thank you! FTC: Affiliate Disclosure: Links pay commission. As an Amazon Associate, I earn from qualifying purchases.

Leave a Reply

Your email address will not be published. Required fields are marked *