Garmin 305 – Retro GPS Test Results Are In – Were The Glory-Days Glorious? Or Rose Tinted?

Reading Time: 3 minutes

Back in 1812 when Garmin released the Forerunner 305, I was young and fast and the world was a generally better place. OK, putting the Napoleonic Wars to one side, it really was a better, faster and more accurate place.

Or so it seemed.


It all started here NOT CLICKABLE

Garmin’s 205/305 were,  at the time, a very popular watch and, to be fair, they were ahead of the sports tech curve. The 305 also probably put Garmin on the path to the sporting watch dominance that they now enjoy. All because they probably sold vast numbers of these and then similarly large numbers of the Edge and 910 and 310 models that followed. And then to the money-spinners that were the Edge 8xx, Edge 5xx and Fenix 3.

I have this recollection of the Instant Pace on the 305 nearly always being ‘spot on’ and I relied on it every week as one parkrun 5k PR/PB after fell and then fell again. Ah yes. The good old days. In some ways the 305 probably also got me started on this blog through getting me keener on running than I had been in the even earlier and even more glorious years.

Anyway. Is it REALLY any good? (For GPS)

It’s packed full of SirfStar III GPS chip goodness. Even now we are only on SiRFStar version V (a la Suunto SPARTAN IV a la Polar V800) and we’re still using the exact same satellites.

Newer chips could conceivably compromise quality in favour of power saving; conversely newer more compact watches might have smaller antennae to fully capture that wonderful GPS signal. Indeed those of you who remember the 305 will certainly remember its size, it certainly WAS NOT compact. So maybe the 305 was just full of a whopping battery and other antennae-signal boosting electronic wizardry similar in capability to your satellite TV dish.

I put the 305 through my GPS test last week. It’s only ever going to have one shot at the test as it’s quite a way to run and other more interesting things will be adorning my wrists over coming weeks.

The test is a hard one. (Details here). The raw FIT/TCX GPS test files of ALL devices are available (here) in a public folder along with an analysis spreadsheet of the summary results (there are three tabs in the spreadsheet).

The result?

A: 73%. I was a bit generous. For old times sake. Now you know.

But that was an acceptable performance. On a par with the Suunto ULTRA when first released and notably above the Garmin Fenix 5X and even above the V800 when the V800 is worn on the underside of the wrist. But the reality is that it is at the lower end of acceptability. It is notably below the SPARTAN SPORT and POLAR V800 (the latter when worn properly) which are in a different class. Although the cynic in me would point out that it scored the same as the Garmin 235.

Also when running at a constant pace I am sorry to say that there WAS notable instant pace variation by the ‘industry-standard’ 30secs/km, or slightly more, on the underestimating side and 5-10 secs/km on the over-estimating side. When running at a constant pace in open skies it WAS pretty good though. But then again, most sports watches are.

The 305 got the overall distance accurate to near-enough +/-0.5%…again that’s pretty normal.

Please feel free to reminisce below and start every comment with “Ahhh! when I were a lad/lass we could only afford coal for breakfast” 



Support this site with purchases at these partners - should click to a local choice in your country
Notify of
newest most voted
Inline Feedbacks
View all comments

Hey there,
I’ve downloaded your excel spreadsheet with GPS test results and noticed that Fenix 5X testing conditions were “LEAF AND RAIN”, where as most of other watches were tested in “NOLEAF&CLEAR” conditions. How big of an effect could it have had on test results you think? Would Fenix 5X results be better in clear conditions?


tfk, the5krunner

very little difference if any.


I still have one in my closet. It lost it’s waterproofing and 3 of 5 side buttons, but still works. GPS lock takes 3min (yes, minutes, do You remember that times waiting already after warmup for the watch to lock GPS 😛 ?), but when it will lock, it works fine, as You confirm, it does not stand out from devices 10y newer! There are 3 unique features that I loved and miss in newer devices: 1. configured smoothing of instant pace with 3 settings available (fast, medium, slow). For interval workouts I always went with fast, for races with slow, and for anything else with medium. (PS: check which one did You have as You mention variations in instant pace? maybe with ‘slow’ setting it would perform better…) 2. advanced workouts could be defined on the device! I know it took ages, but it was an option and I actually used it a lot for quick edits of target paces or number of reps. Miss it a lot! 3. advanced workout mode had 2 extra pages, not just one. The additional one had info about previous lap, like distance, time, av pace, av hr… also miss it a lot.… Read more »


I still use my 305 several times a week (last used yesterday). It refuses to die or be inaccurate enough to justify being replaced.

It does take a while to find satellites, I have a routine where I put it on the windowsill in the evening and the first thing I do in the morning is turn it on. By the time I am ready to go out the door it is ready to go too.


I still get a burst of frisson using my trusty 305. It was the first gps on the market that provided a reasonably-sized wearable device. It also did the principle wonderful thing that gps watches do, by freeing measured workouts from the track. Later surprises included the resilience of the battery, and learning that I preferred the 305’s buttons to touchscreens, (for instance, that on my iwatch). All in all, no consumer item has ever given me nearly so much pleasure.