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Garmin Forerunner 255/255S Review – Loaded mid-price athlete

Tags: Review | Garmin | Smart

1.6.2022 | 11 MIN | 7x comment

Forerunner 255 – this is the best sport smartwatch under 400 EUR. Is this fact enough? No? Well then, it also lasts 14 days, uses mapping for navigation, allows for contactless payments, and there are so many features for your workouts that even the sport icon Coros might be embarrassed.

I'll say it right at the beginning. The Forerunner 255 (FR 255) turned out so well that I don't know why one should purchase the Forerunner 745, which might be a higher class, but also an older, model. Nevertheless, it was one of the best mid-price watches for runners. Now, this is the title of the FR 255.

Generally speaking, the FR 255 definitely improved in workout analysis: whether you're not overtraining, how your body reacts to the training, how well your body regenerates at night, and how to adjust our workout to the data. To calculate the data, it uses heart rate variability (HRV), a value which has been getting more attention lately. The same method uses the competitor's mySassy.

Heart rate sensor – everything about it and how can it help you
Heart rate sensor – everything about it and how can it help you

Treadmill, cycling, indoor cycling, pool swimming.

Hot new FR 255 features:

  • two case diameters – 45.6 mm (1.78") and 41 mm (1.61")
  • almost double the battery life in comparison with the previous generation
  • new heart rate sensor
  • new multi-frequency GPS receiver
  • contactless Garmin Pay
  • morning reports – sleep summary, HRV, training status, and recommended training for that day
  • detailed analysis of HRV at night
  • mapping navigation
  • barometer and gyroscope
  • support of watt measurement during exercise

FR 255 for both men and women

Honestly, making two sizes was a clever decision. For men, the watch would simply be too small. On the other hand, for a woman with slim wrist, it could be too big.

The Forerunner 255 has a diameter of 45.6 mm (1.78") and is 12.9 mm (0.5") thick. The measurements seem to be closer to the FR 955 model, which is excellent. Don't want to pay extra for the FR 955, but you like the size? Take the FR 255.

Výstřižek z naší videorecenze, když jsem natáčel na Valašškém hrbu. :)

A screenshot from our video review that I shot during a race. :) The perfect size, isn't it?

Garmin Forerunner 955 review – Satisfied only with the best
Garmin Forerunner 955 review – Satisfied only with the best

On the other hand, we could joke that the S in FR 255S stands for slimmer – the diameter is 41 mm (1.61"), and it is 12.4 mm (0.49") thick. This probably makes the watch the first purely women's multi-sport watch. The FR 745 could also be considered to be women's, but it was more on the unisex side.

Garmin Forerunner 245
Garmin Forerunner 255S
Garmin Forerunner 255
Garmin Forerunner 955
Case diameter 42.3 mm; 1.67" 41 mm; 1.61" 45.6 mm; 1.78" 46.7 mm; 1.84"
Case height 12.2 mm; 0.48"
12.4 mm; 0.49"
12.9 mm; 0.51"
14.4 mm; 0.57"
Strap width 20 mm; 0.79" 18 mm; 0.69" 22 mm; 0.89" 22 mm; 0.89"
Display size 1.1" 1.1" 1.3" 1.3"
Resolution 240 x 240 px 218 x 218 px 260 x 260 px 260 x 260 px
38.5 g
39 g
49 g
53 g

A colourful line runs around the circumference of the Forerunner and gives the watch that sportish look. We could first see it with the triathlon edition FR 945.

At the same time, there are new grooves next to buttons. The "START" button is, as always, coloured according to the colour combination you opted for. It is the only button which has the option of two levels of pressing to prevent unwanted pauses during training. It has basically become a standard with the Forerunner line.

Let's talk about the buttons in general now. I don't know why, but I feel as if the buttons of the older FR 245 model were of better quality. They were not as "wibblywobbly". But I also like how Garmin paid extra attention to the detail of the buttons, with the shiny sides and matte faces. They are also a bit more sunk in, which is a great decision because if the FR 245 were human, their ears would be protruding.

The transition from case to lugs is taken to perfection. Although the transition with the FR 245 was smooth, it is straight-out stylish with this new model.

Fort fighting for Forerunner's frequency

This is a new feature which Garmin first used with its Fenix 7 and then with the Tactix 7. There is a protective bump, with the heart rate monitor is sunk into it. Until now, there was the chance of scratching the monitor whenever you put your watch down. And now, the watch stands on its own legs. The monitor is now also hidden under glass, not plastic. Yet another feature fighting scratches. :)

The charging connector was also moved to the left for reasons which are unknown to me, and there is a barometer sensor hidden under the serial number. Usually, this sensor would be on the side of the case, and I'm a bit worried that skin will block it and make the results distorted.

And maybe it was somewhat true. Here is a comparison of elevation in metres measured by the FR 245, FR255, and the Tactix 7.

FR 245 – red, Tactix 7 – purple, FR 255 – blue

The strap is attached to the case by the QuickRelease system, which is a huge advantage when compared with the FR 955, which employs classic spring bars.

Besides this, the strap has a nice grid design.

I put the larger variant to a test, and I have to say, it wore very well. It is not as small as the previous FR 245, and not as thick as the FR 955 for example.

Garmin, will you ever choose a different display?

I'm probably starting to feel discontented with Garmin always using the same kind of display. Yes. transflective LCD display is tested and approved, works well, and it probably makes the most sense with the Forerunner line, but... Don't you also think that it's time for a change? Well, Garmin doesn't have to slap AMOLED on its watches, I would probably hate it, but what about some improved LCD?

The fundamental difference between the FR 955 and 255 is that the FR 255 does not have touchscreen.

Anyhow, the display is protected by the Corning Gorilla Glass 3, and I would definitely recommend buying a protective glass. Since the glass is slightly inward, you can hear it calling for it.

Said Gorilla has a great advantage. It does not cause as many reflections as sapphire, which makes watch more readable during movement.

The camera is focusing on my shoes, but do you see the beautiful shine of the display?

However, what was not a good decision is the black frame around the display. It was terrible with the FR 945, the same goes for the FR 955, and the FR 255 is getting closer to this.

Sensors are at the same level as Garmin cutting-edge models

The heart rate monitor is the same it is in giants like the Fenix 7 or Tactix 7, these are watches with price tags around 3 times higher. The new Elevate 4 generation measures amazingly accurately, but the FR 255 has an advantage thanks to its weight. Although metal watches have the tendency to jump around when work, plastic watches stick and don't let go. This makes measuring much more precise.

New GPS receiver – it's just perfect. A gigantic step forward. Mainly because the GPS receiver doesn't only receive GPS + Galileo / GLONASS, but all the satellites at the same time, and multiple frequencies. What does that mean? That the more frequencies they communicate with, the better the chance of receiving the location data and the more accurate measuring and path layout.

You can choose from these modes – only GPS | GNSS | multi-frequency GNSS | Ultra Trac (receiving every minute).

From the classics, there are accelerometer and pulse oximeter. New features are gyroscope (great for recording how many pools you swam and what kind of stroke) and barometer. During the day, it measures floors climbed; during a trail run, it measures meters climbed in real time.

Battery life up to 14 days

When the FR 745 was released a year and a half ago, it has one disadvantage. It lasted 5 days. That's simply not enough.

But the FR 255 can make it up to 14 days in the smartwatch mode, and 30 hours with active GPS. That means it is ready for the Ironman (17 hours), but also some 24-hour long race. For me, any battery life over 25 hours with the GPS on is a sign that the watch is a good choice for any endurance athlete.

Just to illustrate – when I took the FR 255 running, the battery went down by 3.43 % in an hour while multi-frequency receiving of all navigational systems.

Which is slightly over 29 hours during the multi-frequency receiving!

But there is a big BUT. I didn't connect the FR 255 to Connect, the battery life is therefore not affected by Bluetooth and notifications.

For comparison – battery of the older FR 245 goes down by 8.57 % in an hour. The premium Tactix 7 model with the same setting as the FR 255 goes down by 1.71 % in an hour.

User environment? Fastest Garmin (Fore)runner!

I don't know how Garmin managed it, but the FR 255 is simply faster. Using the watch is faster than a bullet. I'm not sure whether it is related to the display (which I hated on a bit earlier) or to a faster processor, but there surely is an improvement.

Other than that, it's our standard Garmin. Menu you can edit in the form of a list, five buttons, and getting to whatever you need with three clicks maximum. Good ol' Garmin.

Morning reports are... brilliant!

The FR 255 offer the classics of Garmin lifestyle features – sleep monitoring, Body Battery (rating your body energy on a scale from 0 to 100), pedometer, burnt calories, all-day long heart rate and stress monitor... but let's focus on the new features.

What's completely new are morning reports, which might have appeared on the Vívosmart 5 band, but it was nowhere near as detailed.

A morning report is a summary of your sleep (length, rate of phases, evaluation), length of regeneration, training status, status of HRV (average variability and a graph of the night), and the daily recommended training.

Analysis of HRV at night takes health monitoring to another level

HRV signals tension of your body on the basis of differences between your heartbeat intervals. If the pauses are long (many milliseconds), it is a sign of being well. If the pauses are short (few milliseconds, very regular heartbeat), it is a sign of your body (or heart) having tension.

Personally, I've been using HRV for a long time, but I've been satisfied only with a shot of health monitoring, which included my HRV. And since it is automatic and is being done throughout the whole night, is perfect. I can look at the development of my nightly HRV, and consequently also how well my body regenerated.

I believe that this improvement of HRV improvement is the biggest step forward with the FR 255.

Yet another improvement, this time of training status

Garmin realised how dangerous it is to overtrain. This is why they added the new Acute Load feature, which evaluates your weekly load and tells you whether it is too much. This is an especially important feature since overtraining could lead to forced rest which would take several months or even years. Or God forbid, even fracturing a bone when fatigued.

Your watch will evaluate the most optimal load based on your physical condition. For some, this might be 100-200. For other it could be 500-700.

It's a shame that readiness for a workout wasn't added to the Forerunner 255, although it was added to the FR 955 model. On scale of 0 to 100, it shows your readiness based on the length of regeneration, physical load or HRV.

Toto je widget připravenosti k tréninku. Ani byste nepoznali, že se jedná o FR 955 a ne FR 255, co?

This is the widget of training readiness. It's hard to distinguish the FR 955 and 255, isn't it?

(100 - Ideal - Full of energy and ready)

When speaking about things missing, the FR 255 doesn't have the Real Time Stamina feature, which at the beginning of your run tells you for how long or how many kilometres can you run under this load.

Heart rate frequency – Chest strap vs FR 255 vs Tactix 7

Overall, it is definitely not bad. The new generation of heart rate monitors does it job fantastically. Generally, it's true that the lighter the watch, the more accurate the measuring. Heavier watches simply tend to jump around on your wrist.


Purple – Tactix 7, Blue – FR 255, Red – chest strap

If we zoom in on this picture, we can see that the Tactix 7 measure a bit better. I have a simple solution for this, the software of the FR 255 is not finished yet (the watch was not officially introduced to the market during this testing) and therefore the algorithms processing the data from the monitor are also not finished. This unfinished software is most likely responsible for these peaks. :)

GPS – FR 245 vs. FR 255 vs. Tactix 7

This is where we can very well see the difference between the previous and the latest generation. The FR 245 often gets you off the road, while the FR 255 and the Tactix 7 data could be mistaken for a single line as they recorded the run identically.

FR245 – červená, Tactix 7 – fialová, FR 255 – modrá

FR 245 – red, Tactix 7 – purple, FR 255 – blue

FR 255 supports Running Power

Some sportspeople now include their performance in watts to their training. When you connect it to Stryd, you can now see your current performance right on your watch. But only when combined with the HRM PRO chest strap!

A smaller (well, big for some) change is that Garmin supports trainings straight from Stryd, which are based on performance zones.

Race Widget – what race and in what time?

The Race Widget is rather an informative feature – it is a widget which shows you information about an important race. Its name, trail details, target time, and how many days till its start. After putting in a GPX file, it will calculate a prediction of your best possible result. This result might change based on the fluctuation of your physical condition. Motivating, right?

But the main idea? Telling you that a race is close and to work your butt off! So, get up, cry baby!

Finally some proper navigation

This was one of the biggest differences between premium and basic models – navigation kind.

The FR 255 got mapping. You can upload a GPX file into your watch and let it navigate you. It's not as clear as using a watch with already installed maps, but it does its job... Takes you wherever you need. :)

(fotka navigace)

Maybe one of the biggest advantages is that the Gorilla Glass is much better for readability. Thanks to it, data or navigation, for example, can be clearly read.

Distance, stopwatch, pace

Pay with your FR 255

Yes, this is very exciting news. You don't have to worry about taking your wallet on your run. Just tap the POS terminal with your wrist, and you've paid.

Music player is only available with the Music version

Up to 500 songs fit into the FR 255, or you can use streaming services like Deezer, Amazon Music, or Spotify. But you do need to have a premium account to download your playlists.

Summary – how is the Forerunner 255?

Simply perfect. And I do have a few clear reasons for this.

The watch has the perfect sensor equipment.

The watch has smart features like music player and contactless payment option.

It can navigate using mapping.

Besides a few exceptions, all the training features are by Garmin.

The battery life is literally long lasting.

And now the main reason – price tag below 400 EUR.

You know, I wouldn't be surprised if the Forerunner 255 ran to be the second most sold Garmin watch within 400 EUR. The Venu 2 is a tough competition, so the first place will be hard to take over.

But as long as we're talking about sport smartwatches under 400 EUR, Forerunner 255 is definitely the winner.


Madilaosago 780 days, respond
Hi! Is there the turn by turn navigation when running?
Dominik Hokago 780 days
Hello Madilaos. Yes, there is turn by turn navigation. :)
Markoago 779 days, respond
I think the you got the strap width wrong on the 255s, seems to be 18mm big difference
Dominik Hokago 778 days
Thanks, Marko. I've fixed it.
Carlosago 744 days, respond
When you refer to the 255s as a women’s watch, is it for the fit? Isn’t it very similar to the coros pace 2 which is unisex? I’m considering changing my pace 2 but don’t want to go much heavier on weight. Thanks!
Artago 530 days, respond
Ahoj, kolik maji prosim ty 255s lug to lug? Diky za info.
Matěj Urbaczkaago 528 days
Zdravím, 255S mají lug to lug 48,5 mm.

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