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Garmin Forerunner 255 review: The best just got better

Our Rating :
Price when reviewed : £300
(or £350 for Music) inc. VAT

The Garmin Forerunner 255 somehow improves on the 245 in nearly every way


  • Improved accuracy
  • Double the battery life
  • New sizes and no price premium


  • Still expensive
  • Garmin Pay support is weak
  • No offline maps

The Garmin Forerunner 255 has a problem; a nice problem to have but a problem nonetheless. With the Garmin Forerunner 245 (£208) still ranking high on our list of the best running watches, how do you improve on a device that is pretty brilliant at everything it does?

As if there was any doubt, the running fanatics at Garmin have found a way to do it. The Garmin Forerunner 255 is a superb running watch, which improves on its 2019 predecessor in a whole host of ways, while still keeping the very appealing basics the same.

The long and short of it is that if you’re in the market for a new running watch and can afford the admittedly high cost of entry, then this is pretty much a no-brainer.

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Garmin Forerunner 255 review: What you need to know

Given the limited power requirements of wearables, enticing runners to upgrade their watches is a lot trickier than pushing them towards a new phone. Still, Garmin has had a good go at it, with a whole heap of improvements that have trickled down from the company’s higher-end wearables.

First up is more accurate heart-rate measuring thanks to the Elevate V4 heart rate sensor that features in both the Venu 2 (£350) and Fenix 7 (£600). Essentially, this has more light sensors, which theoretically means you can get more accuracy without having to put on a chest strap every time you head out.

The new sensor also allows the measurement of heart-rate variability, or HRV. This examines the difference between heartbeats in milliseconds, letting the watch better measure fitness, stress and how rested you are, and allowing it to offer better advice for your daily routine. You can also take a Health Snapshot, which will capture all your metrics, if you’re prepared to sit still for two minutes.

Elsewhere, Garmin introduces multi-band GPS, meaning you can lock onto multiple satellite networks simultaneously for greater accuracy. There’s also triathlon support, a more readable colour memory in pixel (MIP) display, a barometric altimeter to count floors climbed, and Garmin Pay is available too, on the slim chance that your bank is actually supported.

Finally, there’s improved battery life. It’s dramatically improved if you get the 46mm version, which jumps to a massive 14 days; that’s double what the 245 can muster.

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Garmin Forerunner 255 review: Price and competition

For the first time with the Garmin Forerunner series, Garmin has introduced a choice of size options: 41mm and 46mm.

There’s good news and bad news about this. The good news is that they’re the same price, which is welcome given the likes of Apple and Samsung charge a premium for going bigger.

The bad news is that price is high for a mid-range running watch. You’re looking at £300 for the standard model or £350 if you want the “Music” version which, as the name suggests, has built-in storage for music downloads to save you taking your phone out on workouts.

That’s £50 more than the excellent Forerunner 245 launched at in 2019, and gadget prices only go in one direction: three years later you can expect to pay around £200 or less for the version sans music.

In the £300 range, the main opposition comes from the likes of Coros Apex (£300) and the Polar Grit X (£300). Because running watches aren’t refreshed annually like smartphones, both of these are slightly long in the tooth now, meaning they can be had for quite a bit less nowadays, if you shop around.

Garmin Forerunner 255 review: Design

For review, Garmin supplied the full-size Forerunner 255 Music, rather than the smaller 255s. The screen is a 1.3in number with a resolution of 260 x 260, while the smaller 255s has a 1.1in screen with a resolution of 218 x 218. For comparison, the 245 split the difference, with a 1.2in screen and a resolution of 240 x 240.

So it’s larger, but not massively so. The 245 was never exactly hard to read, but this makes it slightly easier to see things at a glance, especially as Garmin has taken the opportunity to improve one of its best features.

Some running watches insist on showing you the data they think is important, but the Forerunner 255 will let you pick your own from a huge selection covering everything from calorie burn to live pace. While the Forerunner 245 capped this at four metrics, the Forerunner 255 lets you have up to six. It’s a little crowded, but it’s brilliant that Garmin gives you the option. I’m still mulling what to do with the other two, on top of my usual timer, pace, average page and distance.

Away from giving you a decision on sizing, Garmin has chosen not to reinvent the wheel here, and this is unmistakably a Forerunner watch, right down to the familiar five-button layout and refusal to embrace touchscreens. If you want a touchscreen, the Forerunner 955 offers that feature but costs a good deal more, starting at £480.

It’s not the most stylish-looking watch out there – more practical than aesthetically pleasing – but it’s worth remembering that, like all Forerunners, you can switch between this and the more stylish Vivomove Style and Luxe ranges and still have your steps and heart rate tracked between wearables.

It’s extremely comfortable on the wrist for extended wear, despite weighing a little more than before at 49g (up from 38.5g on the 245), and the straps can be exchanged for pretty much anything thanks to its standard 20mm lugs.

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Garmin Forerunner 255 review: Performance

The big change in the way the Forerunner 255 works is that it’s now far more proactive in its workout recommendations. Every morning, you’re offered a daily report based on your sleep and the condition of your body, along with a recommended workout. You’re under no obligation to follow the recommended effort level, of course, but if you choose to, Garmin will help you along the way, with a helpful graphic to show you the pace range you need to be in, and beeping furiously if you over- or under-do it.

Although this kind of guidance was already available via Garmin Coach on the Forerunner 245, that was more of an opt-in thing. Here, it feels much more proactive. Even better, if you have a big race planned, adding it in the Garmin Connect app will feed into the new race widget, where the predicted weather on race day, as well as your estimated time, will appear to keep you motivated. Naturally, recommended workouts adapt to the upcoming event.

It seems to work, too, something I found out the hard way when I overdid it on an early run and had to stop. (I suspect long Covid has done a number on me and I’ll never return to my 24-minute 5K best.)

Presumably, Garmin feels confident enough to take this more proactive approach because of all the data its sensors now suck up about your day-to-day condition. Alongside improved accuracy, the main benefit of the 255’s new Elevate V4 sensor is its ability to track heart-rate variability, which be used to assess what state your body is in. It takes three weeks to get an average but, once calibrated, it will tell you what your HRV is every morning. If it’s unbalanced, the watch will encourage rest and more gentle exercise.

All of this would be for naught if the actual exercise sensors were out of whack, of course, but the improvements make the watch better than ever in that regard. Since the Forerunner 245, I’ve found Garmin’s GPS to be pretty much spot on, always measuring my weekly 5km parkruns unnervingly accurately, and the 255 continues that trend. It measured Bicester parkrun at 5.04km, for instance, which is well within the margin of error, especially considering I set off from a bit behind the start line.

It does this with the added bonus of faster lock-on times. The Forerunner 245 was never exactly slow but, as a quick unscientific test, I put both my 245 and the 255 to work getting a lock from the same position in my garden. It took seven seconds for the former, and a mere three for the latter.

While I don’t have a chest strap to compare heart rates, the numbers certainly tally with my experience on runs, and others have noted that they’re close enough to dedicated hardware numbers that they’d feel comfortable running without a chest belt. That’s impressive.

The battery life is much improved, too. Garmin says you can get 14 days with the 46mm model I’m wearing (or 12 days with the 41mm version), and that feels about right. Of course, this drops if you’re doing daily exercise but that still amounts to 30 hours of continuous GPS usage (less if you use multi-band, or listen to music via the watch while working out). That’s about double the Forerunner 245’s offering and, while you can get more long-lasting watches if that’s your thing, charging is fast enough that it doesn’t feel like this should be a dealbreaker, given the watch’s many other obvious strengths.

Said strengths extend to the superb Garmin Connect app, which provides all kinds of nerdy insights, without a paywall. For example, just going out on a simple run provides – deep breath – average pace, average moving pace, best pace, average speed, average moving speed, maximum speed, total time, moving time, elapsed time, average heart rate, max heart rate, average cadence, maximum cadence, average stride length, elevation gain, elevation loss, minimum elevation, maximum elevation, and calories burned.

Phew. If anything, it’s almost too comprehensive, but then the brand is aiming at a more hardcore crowd than Fitbit and the like.

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Garmin Forerunner 255 review: Verdict

Ultimately, there’s very little to object to about the Forerunner 255; it improves on its predecessor in every way, except price.

Even then, considering the upgrades involved – greater accuracy, stronger battery life, heart-rate variability, Garmin Pay, a barometric altimeter and triathlon support – £300 doesn’t seem wholly unreasonable. And it’s impressive that Garmin isn’t charging more for those who want a larger screen, as most other wearable makers do.

And yet, Garmin is kind of a victim of its own success here. If you own a Forerunner 245, as I do, is it worth upgrading to the latest and greatest? Probably not, because it’s still a damned fine running watch and it does the basics so well. If you’re looking for your first sporty wearable and don’t care about triathlons, it’s hard to ignore the fact that it can be had for around £100 less.

Still, that’s probably a good problem to have. When the biggest decision your target market is making is which product they want to give you money for, you must be doing something right.

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