Sport Passion   -  Comparatives, tests, advice and training tips

Test Garmin Forerunner 255 and 255 Music: almost top of the range at an affordable price

by Philippe Baudoin © Copyright (published 16/09/2022)
Test of the Garmin Forerunner 255, running and triathlon watch

A new, much more comprehensive model that should (even more) please many athletes!

New in 2022, the Garmin Forerunner 255 replaces the Forerunner 245. Now available in 2 case sizes, it features new sensors including a barometric altimeter and a dual frequency GPS. It also becomes multi-sport and offers a triathlon profile. Its new functions include native power on the wrist. This new model is similar to the top of the range model in the series but without the mapping and touch screen. We really liked it! Detailed review, full test and our opinion on the Forerunner 255.

Forerunner 255 test summary

Price : 349 € (255) and 399 € (255 Music)
Weight : 39g (255S) and 49g (255)
Dimensions: 41 x 12.4 and 45.6 x 12.9mm
Display: Non-touch MIP, 28 and 33 mm, 218 x 218px and 260 x 260 px
Use: running, triathlon, trail, 30+ sports
Autonomy : 26-30h / 12-14d (GPS / watch)
Pluses: 2 case sizes, dual frequency GPS, barometric altimeter, native running power, Garmin Pay, compact model
Less: Less affordable than the previous model, buttons a bit hard

Verdict: The Forerunner 255, clearly more complete than the previous model, is in our eyes the watch offering the best compromise for most sportsmen. The barometric altimeter makes it suitable for trail running, skiing and hiking. The 2 case sizes offer a perfect fit for all wrists. The sports tools are more complete than those of the previous model. The watch offers a triathlon profile. The dual-frequency GPS is ultra-precise. The higher price is justified by these additions but makes the Forerunner 255 less accessible to everyone. A watch that should still be a hit in the next few years and that is close to the top of the range model but without mapping and without a touch screen. We loved the old model, we loved this one!

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The Forerunner 255 replaces the Forerunner 245. It offers new sensors (barometric altimeter, dual frequency GPS, gyroscope, thermometer) and a plethora of new features

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About this test

For all the tests or detailed reviews we carry out, we do not receive any remuneration from the manufacturer. We do not publish sponsored content on our site. All our tests are brand independent. Our goal is to provide free, neutral, reliable and useful information to help users choose, buy and use sports equipment (watches and fitness equipment).

Go directly to our opinion

Garmin Forerunner 255 presentation: the right compromise for runners, trailers and triathletes

The Forerunner 255 and Forerunner 255 Music from Garmin are 2 mid-range cardio-GPS watches offering full sports functions and GPS navigation (route tracking, etc.). They replace the Forerunner 245 and Forerunner 245 Music, 2 models released in 2019, which were starting to get a bit old. Note that in 2023, Garmin launched the Forerunner 265, equivalent to the Forerunner 255 but with an AMOLED screen. Read our test of the Forerunner 265.

For a detailed comparison between the old and new models, see our Forerunner 245 versus 255 comparison.

Presentation Forerunner 255


A watch that becomes multisport and triathlon

This new model, originally designed for running, is now multi-sport and offers a triathlon profile. In concrete terms, you can chain several sports activities together without having to stop recording one activity to start the next. Just press a button to move on to the next sport.

This makes the Forerunner 255 the cheapest triathlon watch from Garmin. Finally, good news for triathletes who have been looking for an affordable Garmin watch.

It can be used for many other sports, about thirty in total including running, swimming (open water and pool), cycling, hiking, trail running, etc... (see list below in the article)


2 case sizes and a new screen

The watch is now available in 2 case sizes:

  • Forerunner 255S and 255S Music: the smaller 41mm diameter model (instead of 42mm for the Forerunner 245), perfect for thin wrists. The screen is smaller (1.1" instead of 1.2" or 27.5mm) and smaller in definition to fit the new size (218 x 218px instead of 240 x 240px)
  • Forerunner 255 and 255 Music: the 45.6 mm diameter model with a larger screen (1.3" or 33 mm) and better definition (260 x 260 px). It offers greater reading comfort.


running watch and ourdoor available in 2 case sizes


New sensors including barometric altimeter and multiband GPS

The Forerunner 255 brings many new features. In particular, it is equipped with a barometric altimeter and thus becomes usable for the mountains and outdoor (trail, hiking, skiing). We feel that Garmin is preparing its watch for native power on the wrist without an external sensor as Coros and Polar already do. You will find our test of the altimeter later in this article.

Garmin 255 optical cardio
Forerunner 255 features new optical wrist heart rate monitor with oximeter

It benefits from the latest optical wrist heart rate monitor (4 th generation), which is more reliable than the older generation, and a pulse oximeter for blood oxygen level (SpO2) measurements. It is fitted to recent Garmin models.

Multiband GPS

Another big novelty, Garmin equips its watch with a GPS multi GNSS and multiband (L1+L5) capable of correcting errors related to the reverberations of GPS signals, a point particularly useful in the city, in the mountains and in the forest (read our explanations of the multiband GPS and its interest on a cardio-GPS watch). We have tested it: it is excellent (read our test further down in the article and the detailed test in the video.

It is a surprise to find it on a mid-range watch knowing that the standard Fenix 7, which is worth €700, is not equipped with it. To benefit from it on the Fenix series, you have to buy the Fenix 7 Sapphire Solar, which is sold from 900 €...

The watch also has a thermometer (new), a gyroscope (new) and an accelerometer. It can be combined with external ANT+ and Bluetooth compatible sensors (speed, cadence, stride, power, heart rate monitor, etc.).

Summary of features

 Forerunner 255SForerunner 255Forerunner 245
Price (€)350400250-280
Case diameter (mm)4145,642,3
Thickness (mm)12,412,912,2
Weight (g)394938,5
Touch screen
Color screen
Screen size (mm)27,53330,4
Screen size (inches)1,1"1,3"1,2"
Screen resolution (px)218x218260x260240 x 240
Solar charging
BezelReinforced polymerReinforced PolymerReinforced polymer
GlassCorning Gorilla 3Corning Gorilla 3Corning Gorilla 3
Multiband GPS
Barometric altimeter
Wrist cardio
Pulse oximeter
Battery life (GPS only)26h30h24h
Water resistance5 ATM5 ATM5 ATM
Strap size18 mm22 mm20 mm
Interchangeable strap without tools
Forerunner 255: physical characteristics

New features

morning report

Among other big changes, Garmin is adding native running power on the wrist and workouts that include power. To take advantage of this, you need to use an external sensor (running dynamics pods or HRM-Pro belt for example). On the other hand, Garmin does not offer measurement without an external sensor (less accurate though) like Polar and Coros do.

There are new features, some of which are already present on the Fenix 7 and Epix:

  • Enhanced training status that displays progress
  • Morning report: a report constructed each morning summarising the day (consolidation of sleep, recovery and training data).
  • HRV Status (Heart Rate Variability): a new widget displaying general health status (overview of general wellbeing, recovery and performance level) taking into account HRV during sleep.
  • Running widget: to plan your running strategy
  • Garmin Pay to pay for purchases with the watch
  • Daily training suggestions
  • Altitude profile, elevation gain, ascent rate, slope directly on the watch


In addition to these new features, the Forerunner 255 has all the functions of the previous model. It offers more than 30 sports profiles, comprehensive training functions, including the programming of simple or complex training sessions from the Garmin Connect application, running dynamics (stride analysis), comprehensive physiological measurements (VO2max, aerobic and anaerobic Training Effect, training load, Body battery, training status and load, etc.), Garmin Coach, PacePro.

It also offers GPS navigation functions, including route tracking with turn-by-turn guidance and tracking back to the start.

affordable watch for sport


Connected functions and health tracking: Garmin Pay on the watch

Like the old model, Garmin offers 2 versions, one without an MP3 player (Forerunner 255S and 255), the other with MP3 player (Forerunner 255S Music and 255 Music) sold for €50 more. The version with an MP3 player allows you to load up to around 500 music tracks that you can listen to with Bluetooth headphones. You can also listen to streaming music with a smartphone nearby. The two models (with and without MP3 player) are identical in terms of sports features.

The Garmin 255 features contactless payment solution Garmin Pay, offers activity and health tracking and features for security.

The Music model offers Wi-Fi for data transmission (synchronization) and watch updates. Wi-Fi is not essential (Bluetooth does the job just fine) but it simplifies updates to the watch, transferring routes from the application and synchronising data (no need to connect the watch to a PC or switch on your phone to benefit from it).

There are many other smart features such as LiveTrack (for internet tracking), weather, calendar, VIRB camera control and smartphone notifications. The Forerunner 255 has access to the Connect IQ shop directly from the watch.

It offers comprehensive health and activity monitoring. It also includes assistance and safety features such as fall detection and fall assistance with real-time GPS coordinates.

A slightly better autonomy

The Forerunner 255 offers better battery life. However, beware of using the GPS in dual frequency mode. It consumes twice as much energy. This is the price to pay for better accuracy.

Watch mode12 d14 d7 d
GPS mode26 h30 h24 h
Multi-GNSS20 h25 h-
Multi-GNSS and dual frequency13 h16 h-
GPS mode with music5,5 h6,5 h6 h
UltraTrac mode
Rechargeable during activity
Power Manager
Forerunner 255: autonomy


The Forerunner 255 and Forerunner 255 Music are available for sale from €349 and are offered in 8 colours (2 colours per model).

  • Forerunner 255S / 255: €349
  • Forerunner 255S Music / 255 Music: € 399

These prices are €50 higher than the prices of the previous models when they were released, but for a watch that is much more complete in terms of sensors and features. Garmin's best-selling watch is now a little higher, closer to the top-of-the-range model Forerunner 955 but a little less affordable.

Forerunner 255 on fountain


Who is the Forerunner 255 for?

It is aimed at all sportsmen and women, from beginners to advanced. Much more complete than the Forerunner 55 (the entry-level model for runners) and a little less sophisticated than the Forerunner 955 (the top-of-the-range model with mapping), it is perfect for most sportsmen and women, even experienced ones, who practise endurance sports such as running, trail running, cycling, swimming (sea and open water) and even outdoor activities (skiing, hiking, etc.)

Forerunner 55, 255, 955 comparison
Forerunner x55 series compared: the Forerunner 255 (middle) is a good compromise between the entry-level Forerunner 55 (left) and the premium Forerunner 955 (right), with its race-ready mapping


thickness FR 55, FR 255, FR955
The Forerunner 55 (at the top of the stack) is a little thinner than the other 2 watches in the series: 11.6 mm versus 12.9 mm (FR 255) and 14.4 mm (FR 955)


What is the purpose of a watch?

Originally designed for runners, this watch can now be used for over 30 sports. This new model is multi-sport and offers a triathlon profile. The new barometric altimeter now allows it to be used for outdoor activities such as trail running, skiing and hiking (dedicated profiles).

Go directly to our opinion

Technical data

53 g
FR255S: 41 x 41 x 12.4 mm
FR255: 45.6 x 45.6 x 12.9 mm
Color MIP, 1.1" (27.5 mm) at 240 x 240 px (FR255S) and 1.3" (33 mm) at 260 x 260 px, (FR255), Corning Gorilla glass
Autonomy (GPS / multiband / watch modes)
FR255S : 26 h / 13 h / 12 d
FR255: 30 h / 16 h / 14 d

Multi-GNSS and dual frequency L1+L5
True multi-sport
Recommended activities
Running, triathlon, outdoor/outdoor, swimming, hiking, trail/ultratrail, skiing (cross-country, downhill, snowboard) (30+ profiles available)
iPhone, Android, Wi-Fi (Music model). Bluetooth and Wi-Fi wireless data transfer (Music model).
Heart rate monitor
Yes, optical on wrist
Topographical maps
Payment system
On-board music player
Music model only
Telephony / 4G
Barometric altimeter
Yes, auto-calibrated or manual
Yes + storm alerts
5 ATM (50 m), swimming
Running power with external sensor, full sports functions and physiological measurements, route tracking, return to start, altitude profile, battery manager
Other models
Forerunner 245 (previous model)
Forerunner 55 (entry-level)
Forerunner 955 (high-end)
Go directly to our opinion

Forerunner 255 test: design and technical specifications

Lightweight and nice looking case, buttons a bit stiff and noisy

Quickfit 22 bracelet on Forerunner 255

The Forerunner 255 has a lightweight case (only 39g for the Forerunner 255S, 49g for the Forerunner 255) made of composite material. The glass is made of Corning Gorilla, an ultra-resistant glass used in most smartphones. The strap is made of silicone. Its width varies according to the model (18 mm for the Garmin 255S and 22 mm for the Garmin 255). Unlike the Forerunner 955, it is equipped with the QuickFit&trade quick-release system, so that it can be changed easily, without tools.

We tested the "big" model (Forerunner 255) which is 46.5 mm and blue in colour. The watch is very comfortable to wear and looks great on the wrist. We thought that the blue colour would be a bit flashy for everyday wear. On the contrary, the watch is really nice and gives a sporty look. Its blue display screen, which reminds the colour of the strap, looks really good. The small model, which is designed more for women, is only available in pink and grey, which is a shame. The Music models are available in black and white.

Forerunner 255 and size
The 255 model fits even thin wrists
Forerunner 255 at the wrist
The soft wristband is pleasant to wear and is easy to put on and remove

As for size, we were used to the smaller Forerunner 245, which is perfect for thin wrists, but this model is finally well suited for thin to intermediate wrists, probably also for wide wrists.

The strap is ultra soft and of good quality. It is perhaps a little stiffer than the Forerunner 245, but still very comfortable to wear. It is easy to put on and take off and does not wear out after almost a month of testing.

The buttons are a bit disappointing. They are stiffer than those of the old model (same observation for the Forerunner 955) and a little noisy (small spring noise that the Forerunner 245 did not make). It seems that Garmin has pulled on the quality. This is not the case with the Fenix 7 whose buttons are very soft and very pleasant to use.

Finally, the volume of the Forerunner 255's audible notifications is quite high compared to other Garmin watches and this is a bit surprising at first!

Thin watch on fountain


The screen: a thicker border and 6 data fields

The screen of the Forerunner 255 (large model) is comfortable to read, sharp, very readable in the sun thanks to the MIP technology, but also in dark places (forest, etc.) thanks to an efficient backlight which can be adjusted from 10 to 100%. It is set to 20% by default and this is already sufficient. For more comfort, we have set it to 30%.

The bright, sunlight-readable screen offers an excellent display. The backlight is adjustable from 10 to 100%. In these photos, the screen photographed in a slightly dark room without backlighting (left) and with backlighting set at 20% (middle photo) and 100% (left photo).

The black border around the screen of the larger model (255) is thicker than that of the Forerunner 245 and it shows! With the increase in screen size being proportionately greater than the increase in case diameter, one would have thought that the bezel would be thinner. In reality, Garmin has made the bezel so thin that the border has become 1 mm thicker! It's a pity because it doesn't embellish the model.

Forerunner 255 bezel (left) offers a slimmer bezel but, in return, a thicker bezel, which is clearly visible on some displays

The screen of the two watches (255S and 255) has evolved with a display that can now show up to 6 data fields per sports screen. This is very practical even if the display is a little small on the 27 mm screen of the Forerunner 255S.

The fields are enriched. Power fields can be displayed. Some graphs and gauges are also available. With the ascents/decents gauge (2 data in 1), you can display 7 fields on the watch!

Memory, sealing, operating temperature

The watch has 4GB of memory. It is waterproof up to 50 metres (5 ATM), so can be used for swimming but not diving. It can be used between -20°C and +60°C, a wide and rather good range. It should be noted that a watch exposed to direct sunlight can easily reach high temperatures.

GPS test: ultra-precise multi-band GPS

The Forerunner 255 offers multi-GNSS GPS (it can connect to multiple satellite systems at the same time) but also multi-frequency or multi-band (able to receive multiple signals per satellite). The same can be found on the Fenix 7 Sapphire Solar or the Epix, the most expensive models in the range.

Multiband is a real asset because of its remarkable accuracy, which we have seen during our tests (see also our full video below). By receiving 2 signals per satellite and at different frequencies, it offers a better sensitivity and is able to correct certain errors, in particular errors caused by the reverberation of signals against buildings in the city or rocks and trees in the forest and mountains (read our explanations of multiband GPS and its interest on a cardio-GPS watch).

There are 3 modes to choose from:

  • GPS only: for an optimal autonomy (26 or 30 h depending on the model) but a not always optimal accuracy (see the test in our video)
  • Multi-GNSS: for excellent accuracy and slightly higher battery consumption (the right compromise)
  • Multi-GNSS and Multiband: for excellent accuracy but half the battery life


Forerunner 255 GPS test: multiband, multi GNSS, GPS only, UltraTrac. Comparison with the Forerunner 245 and other watches.
BenefitsFaster docking
Greater GPS stability
Greater reliability (track, distance) in areas with poor reception (more likely to find 4 satellites)
More accurate route tracking
Greater accuracy of GPS track, total distance and average pace
Greater GPS sensitivity
More accurate route tracking
More accurate than multi-GNSS alone
DisadvantagesHigher battery consumption2 to 3 times more battery consumption
Advantages and disadvantages of multi-GNSS and dual-frequency GPS

Our tests have shown a significant difference between the 3 available GPS modes (GPS only, all GNSS and multiband + all GNSS). The track is almost perfect with multiband and much more approximate (in comparison) in GPS only mode. The accuracy of the Forerunner 255 is even better than the Fenix 7 Sapphire Solar. It's possible that this is a software enhancement that the Fenix 7 will inherit in future model updates. It is true that multiband is a recent development in GPS watches. It only appeared at Garmin in early 2022.

Downtown GPS testing

We tested the Forerunner 255 in town and in a small village with narrow streets and stone houses. The GPS is very poor in places.

The accuracy of the Forerunner 255's multi-band GPS is remarkable. The passage under the houses to reach the small street of Badier (bottom of the map) makes it almost impossible to hang on to the GPS. Here, the track is excellent for models with multiband GPS (FR 255, FR 955, Fenix 7 Sapphire Solar). The Forerunner 55, in GPS + GALILEO mode, has a little more difficulty in the village and gets lost there. The few zigzags in the upper right corner correspond to a photo break during which the watches were not moving!

testing the Forerunner 255 GPS
Forerunner 255Forerunner 955Garmin Fenix 7Forerunner 55
In the stone village with its narrow streets, the GPS goes very badly in places. The Forerunner 255 tracks really well, better than the Fenix 7 (Click to enlarge)

Further along the road, in a clear environment, the 3 watches equipped with the multiband system make a nearly perfect trace. The track appears on the right side of the road, with a small gap for the Fenix 7 and especially for the Forerunner 55. We can see some slots made on the right (street crossings).

GPS test of the Forerunner 255
Forerunner 255Forerunner 955Garmin Fenix 7Forerunner 55
The 3 watches equipped with multiband GPS offer a near perfect track (Click to enlarge)

At this other location, the Forerunner 255 offers a very accurate track. You can see a small gap of a few meters to the left of the road on 2 occasions like the other 3 watches. The crenulations are clearly visible. The Forerunner 55 (GPS + GALILEO mode) has many more gaps.

GPS test
Forerunner 255Forerunner 955Garmin Fenix 7Forerunner55
The Forerunner 255 and the 2 other watches with multiband GPS track well with a small gap on the left. The Forerunner 55 has a much larger gap (Click to enlarge)
GPS test
Forerunner 255Forerunner 955Garmin Fenix 7Forerunner 55
In this turn, the track of the 3 watches with dual frequency GPS is perfect (Click to enlarge)

In this other test, our goal was to compare the accuracy of the Forerunner 255's multiband GPS with that of 2 other watches equipped with multiband GPS (Coros Vertix 2 and Garmin Fenix 7 Sapphire Solar). To highlight the value of multiband GPS, we also tested 2 watches that are not equipped with it: the Forerunner 245 and the Forerunner 55, both programmed in GPS+GALILEO mode.

The Forerunner 255's multiband GPS accuracy is excellent with near perfect tracking (the same as we found in our test of the Forerunner 955), almost to the metre. The Fenix 7 Sapphire Solar and the Coros Vertix 2 do a little worse in this and other tests we have conducted with these watches. That said, they may not have benefited at the time from the software improvements that Coros and Garmin have made in the meantime. We would have to do the test again later to be sure.

test GPS multiband
FR 255 (multiband)Fenix 7 (multiband)Coros Vertix 2 (multiband)FR 245 (GPS & GALILEO)Forerunner 55 (GPS & GALILEO)
Comparison of the tracks of 3 watches equipped with a GPS multiband with 2 watches which are not equipped. The FR 255's multiband GPS is very precise, with a track that faithfully follows the pavement we were walking on. The track is precise over almost the entire route


Testing the GPS in the forest

The Forerunner 255's GPS accuracy tests are also good in the forest despite a GPS signal that does not always pass very well depending on the location. Overall, we can see the difference between the watches equipped with multi-frequency (Forerunner 255, Forerunner 955 and Fenix 7 Sapphire Solar) and the 2 others (Forerunner 55 and Forerunner 245). That said, the track in GPS+GALILEO mode remains globally good, much better than in GPS only mode, but just a little less accurate than the 3 other watches in multiband + multi GNSS mode.

GPS test FR255 in the forest
Forerunner 255Forerunner 955Garmin Fenix 7Forerunner 55Forerunner 245
In the forest, the Forerunner 255 shows a track globally in line with the Forerunner 955 and Fenix 7
GPS test FR255 in the forest
Forerunner 255Forerunner 955Garmin Fenix 7Forerunner 55Forerunner 245
The track of the Forerunner 245 and 55 (GPS & GALILEO mode) is good but a little less accurate

On the different runs done, the total distance of the Forerunner 255 coincided really well with that of the other watches (Forerunner 955 and Fenix 7 in particular), with several times differences of the order of a meter after a few kilometres of running! (the displays were changing at the same time!). Generally, we had about 0.3% difference at most on average, with differences of up to 1%.

GPS reliability Forerunner 255
On this course, the 3 watches Forerunner 255, Forerunner 955 and Fenix 7 Sapphire Solar recorded the same distance to within 10 meters. The times are different because the Forerunner 955 had the Auto Pause mode activated. The elevation changes are also very similar!


Testing the different GPS modes

We tested the Forerunner 255's GPS in the four available GPS modes by running the same route several times and changing the GPS mode with each new lap.

  • Multiband + all GNSS
  • All GNSS
  • GPS only
  • UltraTrac

The results here are very similar to those we get with the Forerunner 955. In this test (below), the accuracy of the Forerunner 255 in "Multiband" mode is almost perfect. It is excellent but a little less good in "All GNSS" mode and even less good in GPS only mode. As for the UltraTrac mode, we found the same problem of truncated tracks with the latest Garmin watches (Fenix 7, Forerunner 255 and Forerunner 955. The Forerunner 55 does not offer this mode), a problem that does not appear on the Forerunner 245. The total distance recorded, however, is still correct. It's a pity that this UltraTrac mode is unreliable, because overall, on the well-recorded parts, the track was not as bad as one would have expected!

test 4 GPS mode FR255
Multiband & all GNSSGPS onlyUltraTracAll GNSS
A perfect track in GPS multiband & multi-GNSS mode, a bit worse in multi-GNSS mode, even worse in GPS only mode and truncated in UltraTrac mode

In conclusion, the Forerunner 255's multiband GPS displays impressive accuracy and even slightly better than the Fenix 7 Sapphire Solar (the premium model that costs €450 more! It remains to be seen whether the next update of the model will correct this). We made the same observation during our test of the Forerunner 955 which offers an accuracy equivalent to that of the Forerunner 255. The track is very precise and the accuracy remains optimal even when the GPS signal is poor. The Multi-GNSS mode also offers excellent accuracy, but not as good overall. The GPS only mode shows a good track but much more approximate than the multi-frequency one. You can really see the difference between the 3 modes.
Go directly to our opinion

Altimeter test: reliable and accurate

Forerunner 255 is equipped with a barometric altimeter (new). It offers a much better accuracy than GPS for altitude measurements but especially for the evaluation of the difference in altitude (ascents / descents) in particular for outings on bumpy terrain (frequent ascents / descents). The measurement, obtained from the atmospheric pressure, is very precise, much more precise than that displayed by the GPS, provided of course that the watch is properly calibrated at the start and during the ride if the atmospheric pressure varies. Moreover, the Forerunner 245 did not display the altitude differences on the watch, but only in the application and after correcting the data according to the GPS positioning! If you do not activate the automatic correction, you generally obtain rather crazy values.

The watch can be calibrated manually (recommended at the start) or automatically during the activity. The GPS is used for this. To ensure optimum accuracy, calibration is only done when the GPS signal is strong and only when the atmospheric pressure varies. Note that even if the calibration is not done at the start (or if the automatic calibration uses a slightly inaccurate GPS altitude), the watch will display accurate altitude changes thanks to the barometer.

In our tests we left auto calibration on (the default setting) but took care to calibrate the altimeter properly at the start. For the Fenix 7 tested in parallel, we disabled the automatic calibration, at the risk of seeing some deviations in case of atmospheric pressure variation.

Our tests have shown that the altimeter is very accurate and that the automatic calibration works well, which is not always obvious as the watch has to trust the GPS in case of atmospheric pressure variations.

In this example (forest test), the 3 watches equipped with a barometric altimeter show excellent accuracy and similar tracks. The Forerunner 55, which uses GPS for altitude, shows a more approximate course, depending on the quality of the GPS signal. The measured elevations are so bad that Garmin makes a correction in Garmin Connect using the GPS data (elevation deduced from position and reference maps).

Barometric altimeter test
Forerunner 255Forerunner 955Garmin Fenix 7Forerunner 55
The barometric altimeter on the Forerunner 255 is very accurate. The plot is very similar for the 3 watches with a barometric altimeter (Click to enlarge)

The elevation calculations are accurate and consistent even on bumpy terrain (small climbs and descents that the GPS alone is unable to appreciate correctly).

Altimeter reliability
Forerunner 255 has an accurate barometric altimeter and provides reliable elevation calculation even on bumpy terrain

In conclusion: the Forerunner 255 is very accurate when it comes to altitude readings and elevation gain (ascents / descents). The automatic calibration during the ride works well too.
Go directly to our opinion

Sports functions

30 sports profiles

In terms of sports functions, Forerunner 255 offers all the tools you need to do sports, train, monitor your progress, improve your technique or compete. It has almost all the tools of the top-of-the-range Forerunner 955. It's perfectly equipped for leisure sports, but also for training, preparing for or running an event.

Its thirty or so sports profiles will suit most users. Here is the complete list to date:

  • Outdoor endurance: running, trail running, virtual running, track running, cycling, swimming (pool, open water), walking, hiking, ultra deep, electric cycling, mountain biking, eVTT
  • Triathlon, multisport
  • Winter sports: skiing, snowboarding, cross-country skiing
  • Water sports: stand up paddle, rowing
  • Indoor sports: treadmill, weight training, HIIT, cardio, yoga, Pilates, elliptical, stepper, rowing machine, stair climbers, indoor cycling, indoor running,


6 data fields
The screen can display up to 6 data fields including graphs and gauges

As described above, the customisable sports screens can display up to 6 data fields. Garmin is expanding the list of data fields and adding the ability to display gauges and graphs.

This model has all the features of the Forerunner 245 and offers new features, some of which are inherited from the Fenix 7:

Native running power and power-based training

Native power at wrist

Garmin now offers native power on this model. It allows you to display running power and to program and track power-based workouts.

Unlike Polar or Coros, the function requires an external sensor (HRM-Pro cardio belt or Running Dynamics Pod) but there is no longer any need to go through a third party application to be loaded from Garmin Connect. This makes things much simpler, although we would have liked a sensorless solution. That said, with the barometric altimeter now present on this new model, Garmin is able, through a software update, to offer this at any time.

Race widget

A new Race widget provides additional help to runners in preparing for a race. This feature provides training tips and suggestions as well as a race time prediction based on the planned date of the event, the goal set, the recorded performance and the expected weather on race day. This is an additional tool to the daily training suggestions.

VFC status

VFC status

Garmin offers a continuous measurement of HRV (heart rate variability) during sleep. The data is used to assess general health, recovery and performance level.

The watch needs 3 weeks to evaluate the average VFC which will then be used as a reference to indicate the state of form in the form of an easy to interpret gauge. While waiting for these 3 weeks, we can already know the value of the last night as well as a graph for the last night and the average of the nightly VFC over 7 days.

Morning report

This new report is displayed in the morning when you wake up and summarises some essential data: sleep quality, VFC, training suggestions for the day, and the day's weather. You can program the indicators to be displayed.

We advise you to set your sleeping time wide enough to avoid being woken up in the morning by the screen turning on!

morning report screens
screens morning report
The morning report summarizes the essential data to start the day and prepare for the next workout


Daily training suggestions

Daily Training Suggestions, already available on Forerunner 55, provides recommendations for activities to maintain your fitness levels. They are based on past workouts and current fitness level. They take into account training status and load, VO2max, recovery time, sleep data, past training data (running and cycling only).

The feature has been enhanced to provide workouts over the whole week instead of day-by-day suggestions. They adapt according to training, performance and recovery and take into account upcoming races

Other new features

Garmin is fine-tuning features such as run time predictor, status and training load.

Thanks to the barometric altimeter, the watch displays in real time the positive and negative altitude difference (ascents / descents) and the percentage of slope.

The functions already present on the old model

The Forerunner 255 has all the functions of the Forerunner 245. You can find a description of these in our detailed model review. Here is a summary of the main features:

  • Sports coach: free adaptive training programmes that can be used for example to prepare for a race (5 km, 10 km, half-marathon, marathon)
  • Running time predictor: the watch indicates the estimated time to run a 5 km, 10 km, half or marathon based on past training
  • Programming of simple and complex workouts
  • Future elevation profile
  • PacePro: a useful function for managing your pace according to the difficulty of the terrain (the watch calculates the best pace according to the effort to be made and the goal to be reached). The function can be programmed in Garmin Connect or directly from the watch by simply indicating a time or pace objective.
  • Running dynamics (stride analysis): stride length, vertical oscillation, ground contact time, right-left balance, etc.
  • Training status: indicators of whether training is optimal (balance between core, aerobic and anaerobic, VFC status, VO2max, acute load)
  • Comprehensive physiological measurements: VO2max, VO2max adjusted for trail conditions, lactic threshold, training effect, recovery time, etc.
  • Assessment of heat and altitude acclimatisation


Go directly to our opinion

Testing GPS navigation and outdoor functions

The Garmin Forerunner 255 offers advanced GPS navigation features including track display, route tracking, backtracking and turn-by-turn guidance. It also has a number of useful outdoor tools such as a compass, thermometer, weather, barometric trend, storm alerts and moon/sun information. Most of these features were not available on the previous model.

To follow a route , you must first create it in the Garmin application and load it into the watch, or load an existing route (GPS file for example) or navigate along a route already saved on the watch (in this case, you will not benefit from turn-by-turn guidance).

The turn-by-turn guidance is very effective. The watch displays the upcoming turns with the distance to the turn. It emits a very audible beep (a bit too much for our taste) and/or a vibration. It is better to deactivate them because they are frequent. We would have liked Garmin to indicate only the tight turns (as Suunto does very well).

If you go off course and catch up later, the watch finds its bearings and resumes its guidance as if nothing had happened.

Route tracking test
The Forerunner 255 allows you to follow a programmed route with turn-by-turn guidance (pictured left). It allows you to retrace your steps.

It is unfortunate that the zoom (cropping) applied to the map does not constantly remain at the value you have given it. The watch resets it after a few seconds and this is quite frustrating when you try to follow the track closely so as not to miss a junction (when you want to retrace your steps or follow a route you have already completed, as turn-by-turn guidance is not available in these cases).

elevation profile
The elevation profile was already displayed on the old model. The new barometric altimeter now allows new data to be displayed (vertical speed, slope, vertical drops)

New to the model, the Forerunner 255 displays speed of ascent, gradient, percentage of slope. All this is in addition to the existing altitude profile display.

The watch is able to calculate distance and 3D speed, useful data in the mountains when the slopes are steep (trail, climbing, hiking).

In conclusion:The Forerunner 255 offers excellent GPS navigation. The turn-by-turn guidance is efficient and accurate. We appreciate the new tools: vertical speed, slope, elevation change. The zoom (cropping) could be improved to make navigation more convenient.

Autonomy test

8 to 25% more autonomy

Garmin improves the autonomy, especially on the big model. We go from 24 hours to 26 hours for the Forerunner 255S and 30 hours for the Forerunner 255 in GPS only mode. The multiband divides this autonomy by 2.

In practice, on the 255, we found about 12% battery consumption per day for one hour of sport in multiband GPS mode. This includes the display of about ten notifications and the use of the automatic backlight in sport mode only. This means that the watch can be used for 8 days without recharging. One hour of sport consumes about 6 to 7% of the battery (still in multiband GPS mode), i.e. about 14 to 16 hours of autonomy, which corresponds roughly to the figures announced by Garmin (16 hours for this model).

The watch charges in about 1.5 hours (40% in 30 minutes). It can also be recharged during sport, but you have to take it off your wrist to be able to connect the charging cable! However, do not try to recharge it via a PC during an outing (for example during a refuelling break). The watch is detected as a USB stick and this stops the activity in progress! You can connect it to an external battery and continue to access the functions.

A new power manager but it is restricted

The watch embeds the new power manager present on the Fenix 7 but in a much less complete way, so much so that its interest is meagre. It allows you to activate the power saving mode in watch mode (the watch can thus last more than 2 months with a basic display, a brightness set to the minimum, the deactivation of the optical cardio and the activity tracking). The power manager also allows you to indicate whether you want to know the percentage of battery remaining and the estimated battery life. The same tool is found on the Forerunner 955.

Battery manager
The watch has the new power manager on board but this, like the one on the Forerunner 955, is much more limited than the one on the Fenix 7.

The Fenix 7 offers a much better battery manager. It allows you to set predefined or personal battery modes where you can specify the GPS mode, which sensors to use, etc. That said, it is quite complex to use and can easily lead to misconfiguration, especially when selecting the GPS mode.

Go directly to our opinion

Activity tracking and connected features

Forerunner 955 offers comprehensive activity and health tracking including sleep tracking on the watch. It displays a sleep score out of 100 that takes into account total sleep time, duration of different sleep phases (REM, deep, light) and stress level.

sleep tracking
The sleep tracking widget

A new "Health snapshot" widget allows you to assess the main health indicators: heart rate and its variability, stress level, breathing rate, SpO2, by means of a 2-minute test at rest. To start a session, select the "Health snapshot" activity in the sports activities (top right button). The results of previous sessions can be found in the Health overview of the Quick overviews (press the DOWN button).

Health at a glance

The "Steps", "Stress" and "Body battery" widgets display the number of steps, the stress level and the energy available for the day as well as a graph of the week displaying the average values. Garmin has simplified the displays by removing the display of the average value calculated for the week. A pity!

health widgets
Garmin simplifies some widgets. The 7 day average of steps, distance and stress level is no longer displayed. This is a shame.

The watch offers many connected functions. Here are the main ones.

A new feature allows direct access to the Connect IQ shop from the watch (via phone or Wi-Fi) to download new watch faces or data fields.

All Forerunner 255 models can control music from a smartphone (in addition to the MP3 player on the Music model).

Garmin Pay, the contactless payment solution that allows you to pay directly with your watch, is now available on this model.

There are functions to be followed live on the Internet (LiveTrack) and to send predefined messages (real-time event sharing) to friends.

Forerunner 255 can detect falls and send an SOS message if assistance is needed.

It can control a VIRB camera and can be connected to a home trainer or an electric bike. It is compatible with VARIA lights and radars.

It displays the weather, a calendar and other useful tools.

To sum up, it really does offer a lot of useful functions for sports and everyday life.

Weather functions
The Weather widget displays the weather over several days (shown here on Forerunner 955)

The application

Garmin offers the Garmin Connect application on PC and Smartphone. It provides access to all recorded data (activity, health). The application displays all the data recorded by the watch as well as complete graphs.

Garmin Connect application
Garmin Connect application
The application on Smartphone (also available on PC). Here is an example of an activity performed with the Forerunner 955 (some data are not available for the Forerunner 255, like the Stamina).

The application provides access to a number of tools for tracking health data, creating a training programme and creating a route. Creating a route is easy with just a few clicks. You can let the application suggest a looped route based on a given sport (trail, running, cycling, mountain biking, gravel biking, other), a given starting point, direction and distance. Alternatively, you can draw the route yourself by marking points on the map. Once the route has been defined, it can be transferred to the watch.

Garmin offers on the Forerunner 255, the synchronization of settings from the watch to the application and vice versa. This is very practical. Similarly, if you have several Garmin watches, you can use each one as you wish (a watch for sport, a watch for everyday use for example): the application synchronises certain data between the watches (number of steps, VO2 max for example) and consolidates the activity data in the Garmin Connect application. There is no need to declare a watch when using it. The platform can manage several watches in parallel.

Our opinion

The Forerunner 2x5 series (235, 245, 255) is a key series in the Garmin range. It is the American company's most successful watch, the one that appeals to the most sportsmen and women in the world, especially runners, for its comprehensive functions including GPS navigation, all at an affordable price.

This new Garmin Forerunner 255 / 255 Music model has almost nothing to do with the old one. Multisport and triathlon, with better components (4ème generation optical monitor, bigger and better definition screen on the big model, barometric altimeter, ultra-precise dual-frequency GPS, thermometer, gyroscope), richer functions, including wrist power, more complete tools for the runner's training, the watch is very close to the top-of-the-range Forerunner 955 model. It is the mapping, the touch screen and, depending on the model, the autonomy, which makes almost the only difference.

The Forerunner 245 was our favourite running watch because of its comprehensive functions, compact size, low weight and affordable price. The Forerunner 255 offers much more for not much more. It's definitely an excellent choice.

my opinion on the Forerunner 255
The Forerunner 255 is an excellent choice of watch offering complete sports functions and all the useful sensors for the outdoor

With the new barometric altimeter that was missing on the previous model, the watch can now be used for trail running, hiking and skiing. The power measurement on the wrist is a great asset for training (more efficient than training based on heart rate) even if we would have liked to see a solution without external sensor like Polar or Coros.

We appreciate the new multi-band GPS which offers impressive accuracy. The claimed accuracy of multiband is no longer just theory or a sales pitch to sell the watch, it has become a reality. This GPS really makes a difference to other modes, especially in places where the GPS signal is not as good or where there is reverberation, such as in the forest, in the mountains or in the city.

The slightly better battery life, which is sufficient even for relatively long runs, will suit most sportsmen and women. The MP3 player is a plus for sportsmen and women who like to do sports with music without having to carry a phone with them. Those with a limited budget can save €50 by choosing the model without music.

A sporty and versatile cardio GPS watch

Finally, the 2 case sizes allow more flexibility with a better reading comfort and a watch better adapted to wide wrists. The only regret is that Garmin only offers the small model (255S) in 2 colours: pink and grey. This limits the choice for men knowing that the Forerunner 245 (of similar size) existed in more varied colours!

The price, €50 more than the Forerunner 245 at launch, is largely justified by the additional sensors and features. It's also now the cheapest of Garmin's triathlon watches. That said, it is becoming less affordable and may encourage athletes who are prepared to do without GPS navigation to prefer the more comprehensive and significantly cheaper Forerunner 55.

Given the features offered for the price, this model should be a hit but also overshadow the models just above it in the range (Forerunner 645 and Forerunner 745). These will probably not be renewed.


The Forerunner 255 is much more complete than its predecessor and in our opinion is the best compromise watch for most sportsmen. The barometric altimeter makes it suitable for trail running, skiing and hiking. The 2 case sizes offer a perfect fit for all wrists. The sports tools are more complete than those of the previous model. The watch offers a triathlon profile. The dual-frequency GPS is ultra-precise. The higher price is justified by these additions but makes the Forerunner 255 less accessible to everyone. A watch that should still be a hit in the next few years and that is close to the top model but without mapping and without a touch screen. We loved the old model, we loved this one!

We liked
  • Multi-band and multi-GNSS GPS, ultra-precise
  • The presence of a barometric altimeter
  • Native running power
  • 2 case and screen sizes
  • 6 data fields per screen
  • The new sports functions
  • 30+ sports profiles
  • An MP3 player (optional)
We disliked
  • Limited colours for the 255S model
  • Basic power management compared to Fenix 7
  • Somewhat stiff and noisy buttons

Price and availability

The Forerunner 255S/255 and Forerunner 255S/255 Music are available in 8 colours (2 colours per model) for €349.99 (255S and 255 models) and €399.99 (255S Music and 255 Music models). Discover them at our partners at the best price and take advantage of coupons de réduction on our site.

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Philippe Baudoin
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