Garmin Forerunner 255, more sizes and functions. First impressions


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Today, the new family of Garmin Forerunner 255which becomes a complete series because, unlike before, it will be offered in two different sizes. The most common size for the watch in this range of Garmin will be the FR255S, while the FR255 without denomination has grown to 45.6mm.

These will not be the only two models available, there will also be versions with or without music playback, in this case replicating what already happened with the last generation.

But not everything is limited to offering different sizes, there are many more novelties. So much so that now the separation line with the Garmin Forerunner 955 (also introduced today) is getting smaller and smaller. In fact the Forerunner 255 becomes a triathlon watch because it supports this mode along with others such as open water swimming, something that has never happened before.

We have many of the features that have been introduced with the top-of-the-range model: multi-band satellite reception, pulse variability monitoring, long-lasting autonomy... Let's go through all the new features.

Buy Garmin Forerunner 255

What's new Garmin Forerunner 255

In many ways the Garmin Forerunner 255 is a trimmed down version of the new 955. Fewer features but you may not use them, so maybe it becomes a better candidate for your use. These are the new features of the FR255, and later I'll specify what it lacks compared to the more expensive model.

  • It becomes a family and there are two versions available, Garmin FR255 and Garmin FR255S. The difference is the size. There are music and non-music versions of both.
  • 1.3″ display on FR255 and 1.1″ display on FR255S (FR255 used 1.2″ display). No touch control
  • The FR255 is 45.6mm in diameter and the FR255S is 41mm. 49 grams and 39 grams of weight respectively.
  • Garmin Elevate V4 Optical Pulse Sensor, which was released with the Garmin Venu 2
  • Multiband (dual-band) system on all versions
  • With barometric altimeter
  • Up to 30 hours with GPS use on 255, or 26 hours on 255S version
  • Morning report indicating readiness to train based on quality of rest, training load and pulse variability
  • Pulse variability monitoring (HRV or HRV)
  • Heart rate variability (HRV) is used as an additional piece of data when displaying training status to try to be more accurate.
  • Training status screen with more values: VO2Max, HRV and load status for the last 7 days (ATL or fatigue in TrainingPeaks).
  • New watch face that allows you to switch between different values to be displayed such as VO2Max, heart rate, etc.
  • New race widget with days to test, weather at that location and more details based on your history
  • Running power estimation with external accessory (HRM-Pro sensor or Running Dynamics Pod)
  • Possibility to change settings from the watch or, finally, also from the mobile application
  • Triathlon and open water swimming profiles are available.
  • HIIT profile for recording activity, with animated workouts and instructions. It was released with the Garmin Venu 2
  • Garmin Pay is available in any of its versions.
  • Direct access from the watch to the Connect IQ store to update items via WiFi
  • Available in five colors: white, black, pink, blue, gray. Not all are available for all versions, depending on sizes and if they have music.

The qualitative leap that has given the Garmin Forerunner 255 with respect to the 245 is very large. Not only in overall performance, but also in the type of watch. It has ceased to be a watch intended for running to become a complete triathlon watch. So much so that right now the 745 is totally out of the game and in many ways can be a perfect replacement for the 955.

Differences between Garmin Forerunner 255 and Garmin Forerunner 955

As I said, in many aspects it offers almost the same as the new Garmin FR955, so as I promised you before... what are the features of the top of the range model that the 255 does not have? The most important ones are listed below:

  • No solar-charged versions available
  • The screen of the 255 is not touch-sensitive
  • No maps, although it does have route navigation
  • No ClimbPro for navigation
  • Stamina metric is not available in the 255
  • It does not have the Training Readiness algorithm.
  • Reduced autonomy
  • Less internal memory for music download

But we do have everything else, such as multisport profiles, compatibility with almost all sensors (and those that are not compatible you will probably not use), updated training metrics, navigation with Up Ahead function, Garmin Pay...

That is, practically the same functions but from 349€ (399€ if you want it with music). This is 200€ less than the more expensive model, so if you are not going to use all these functions, the 255 will offer you everything you need.

Pulse variability monitoring on FR255

At the level of training metrics the adoption of pulse variability is undoubtedly the most interesting novelty. This is not something that Garmin has done as totally new, there are already other manufacturers such as Oura or Whoop that are doing similar things, but in those cases it involves the payment of a monthly fee.


There are also apps like HRV4Training, Elite HRV, etc. They haven't discovered the wheel, but it is interesting that the same device you use for training is the one that records all the data at night.

Pulse variability is the time that passes between each heartbeat (because we are not a machine, there is a millisecond difference between each beat). If the time between beats decreases, it may be indicative of fatigue.

To obtain the necessary data you have to create a baseline against which you can compare the data every night. To do this you have to wear the watch at night for about three weeks to create this baseline, and the more time you spend, the more reliable it will be because the depth of data will be greater.

Once the base is created, the watch will compare the data obtained and combine them with the data of load and training status, intensities, rest, etc. to make a report every day in which it will say if the body is in perfect condition to face a strong training or if it recommends us to take it easy.

The only difference from the Forerunner 955 is that the 255 does not have a Training Readiness metric. This metric offers a score from 0 to 100 and is fed by data on rest, training load, pulse variability, recovery, etc.

But that does not mean that it does not benefit from pulse variability recording, because it is also present in 255.

Garmin FR255 - HRV

As in 955, it does not limit itself to providing the average data of the previous night, but also offers a comparison with respect to previous days and gives an information message to try to clarify the meaning of what it is telling us.

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The morning report, which also uses HRV data, is available. It is the first screen we see on the watch when we wake up with a summary of sleep, pulse variability status, weather, the training we have programmed for that day, etc.

Garmin FR255 - Morning report

In general the pulse variability is fully integrated into the other metrics. For example the Training Status function will now also take into account HRV (and other metrics such as acute training load).

In short, everything is the same as the 955 except for the inclusion of the all-encompassing metric of training availability. That has been reserved for the high-end model.

Running power

At last the power estimation in race comes officially to Garmin. Until now it was available with its own Connect IQ app in beta status, or through third party accessories like Stryd. But the main problem is that it was not integrated into the system for all other functions.

Things as basic as having power zones, seeing data in the end of activity summary or even the possibility of having your training plan based on power. That is, in the end for Garmin is not just to show the instantaneous power, is to integrate it into its entire ecosystem and that is what has taken more work.

But unlike other manufacturers, Garmin needs to use an external sensor to display power data. Recall that both Polar and COROS do this without the need for external accessories, just using data from the watch's own sensors.

Unfortunately the implementation does not include external sensors to use it natively, as for example Stryd, so in this case we have to continue using the different applications that are available in Connect IQ and that are frankly good. But the most comfortable would be poder using it with the native implementation of Garmin.

Undoubtedly, the reason that the Garmin FR255 has received the barometric altimeter is none other than poder support the power estimation in race. It is essential to have this component, because it is the way in which the watch knows whether we are going up or down a slope and therefore supply that data to the calculation algorithm.

I don't want to go into too much detail about running power, mainly because I've talked about it enough in the past. If you have any doubts, I recommend you to take a look at the complete guide to power training which I published both on the web and in the YouTube channelor in the video I made together with Jaime Menéndez de Luarca (Triluarca) also on the same subject.

I do want to add that regardless of the data and how they are, the adoption of the power in race by Garmin is a very good news, because it is the definitive backing for this metric.

It is not that Garmin is the pioneer or who leads the singing voice, but in the end they are the ones who sell the largest number of devices so they are the ones who will bring it to the general public. Although perhaps as it depends on an external accessory not everyone will know its possibilities.

Garmin Forerunner 255, availability and pricing

The availability of the different models depends on the size you are interested in. The large Forerunner 255 is available now in both the regular and music version.

The smaller Forerunner 255S, in both music and non-music versions, will not be available for a few weeks.

In terms of price it doesn't matter what size you are interested in, it doesn't affect how much you are going to spend. It does of course in case you want the version with music:

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

Opinion Garmin Forerunner 255

The Garmin FR255 is a very important qualitative leap for the mid-range Garmin model. And in fact I think it is probably one of the best price/performance ratios on the market right now.

It may seem that a price starting at 349 € is high, especially if we compare it with the latest offers that the 245 has received, but the reality is that they are two very different models. The 255 should be compared with the FR745, a model that it has overtaken in everything (almost everything, because the 745 does have ClimbPro).

For 349€ we have a multisport watch with multiband satellite reception (something that was previously only available in models twice its price), good autonomy, Garmin Pay, altimeter, implementation of pulse variability in different functions of the watch, creation of recommended workouts based on our career, estimation of power in running ... And also offered in two different sizes.

Contrary to what has happened with Garmin in its last presentations, I consider that both this FR255 and the FR955 offer a good price/performance ratio. In fact, both are going to make a significant impact on the Fenix 7 range, which is significantly ahead of the Fenix 7 in terms of price.

And... thanks for reading!

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  1. First of all, thank you for being at the forefront with the news. It is evident that Garmin takes a very strong step forward. A question comes to my mind, which I do not know if you want to answer; in what place are Suunto and Polar after this pull of Garmin, precisely at these price levels? Suunto with its 5 peak and without barometer or running power I see it closer to the basic polar pacer at a higher price and the pacer pro that a priori was a master move for sales now with the 255 everything points to that part of those sales go to Garmin and my second question and being clear: is there really place in the future of polar and suunto after this move of Garmin precisely going to compete in price and performance? I get the impression that Garmin and to a lesser extent coros are giving an acceleration that polar and suunto are not managing to follow and I do not see clear the future of the latter.

    1. Yes, the 255 is undoubtedly a very big blow to the rivals, mainly because it attacks the assets on which they were relying until now. It attacks the part of control and rest analysis which was the trump card of Polar, and the good performance of GPS which was the trump card of Suunto. And I think this is a bad thing for the market and for customers, because if the balance is tilted too much to one side it will create a kind of monopoly.

      Polar, Suunto and to some extent COROS can't compete on price/performance, but what they have to do is do smart and interesting things and get their heads around it.

      1. Well I totally agree, I've been using polar for almost 20 years (except for a Garmin 305 I had) and the truth is that there are things I miss from rs800cx and cs600x , it is true that they are another world today but there are details of customization of training zone that has lost while Garmin and coros are adding new features (different is that these functions work) in my case that I do MTB and gravel is even more dramatic hehehe,I've been years with the 460 and I resist to change but it seems that polar is giving us kicking us in the ass to throw us cyclists ......anyway.

  2. Let's see if it is the replacement for my Vivoactive 3, which is crying out for a new battery, although we will have to wait for better prices.
    Congratulations and thanks for the review.
    By the way, I don't understand how to subscribe to the comments without commenting, because I click on it and it takes me to the subscription administration?

  3. Hi, Eduardo.
    Congratulations for the work you do, your reviews and advice help a lot....
    A quick and difficult question... The 255 or the polar pacee pro.
    The use would be mixed running, city and some trail. Middle distance without doing ultras...

    Thank you!

    1. For pure performance the 255 is going to be a hard rival to beat. However, it also depends on which platform you are more comfortable with, because if you are a Polar user and what the Pacer Pro offers is enough for you, I personally like the application more. Although as I say, the 255 offers some extra functionality.

  4. It is clear that today there are only two logical options:
    O Garmin, o Choirs

    Both have "eaten" Suunto and Polar.

    1. Polar needs to incorporate more software level solutions, it has been at a standstill in that regard for some time now. Suunto right now is an unknown quantity after the purchase by Liesheng. There should now be more capital and development capacity, but we won't know the new owner's intentions until we see the new Suunto model.

  5. Hi, Thanks for the information. Regarding the differences with the FR245 I have some doubts:

    1)Do we have display light control or automatic light (in the FR245 it did not look good in many occasions and did not allow to modify it).
    2) Has the sleep study improved and does it detect naps? If not, I think the body battery will give unrealistic values.
    3) have they polished the multisport? The FR245 in pool swimming was really limited. Any comparison video shows flaws in the strokes, lengths ... It always seemed to me a watch for running without providing reliability in swimming.

    Many questions... I know... Hehe. Thank you!

    1. No, the illumination is on or off, there are no different levels.

      The sleep record is exactly the same as the one you have in 245, there are no changes.

      Personally I have no problems with the swimming record. Keep in mind that everything depends largely on making clear movements that the watch can interpret, if you do strange things that's when the problems will come.

  6. Hi, I come from a 645 that is getting on in years.
    Which would be a better buy today to replace it if they were at equal price? A 255 or a 745
    Thank you

  7. Hello,
    Is the screen size over the 645 (I came from this one) considerable? I had a Fenix 3 and it was too big for my wrist, hopefully all colors will be available in both ranges? Right now it is very limited. Thanks for your work

    1. The display is larger than the 645, as is the diameter of the watch, but not as large as the Fenix 3.

      As for colors Garmin does it that way, some are for the normal version and others for the version with music, but they are not combined with each other.

  8. Hopefully it measures open water well; I had a 735 that was going great and I had to change it. I recently switched to the 935 because it was very cheap, and in open water it is a disaster, apparently because of the "watch aesthetics" according to the Garmin support. I am going to have to buy another one and this 255 if it measures well in open water will be my candidate.

    1. The improvement in open water in the chipsets has been quite remarkable. Already with the 745 the results were quite good, in this case with the multiband chipset the results can be even better (within the difficulties offered by the peculiarities of signal loss).

  9. Hola, lo primero gracias por la reseña, tien muy buena pinta. Sabes si tiene control del brillo de pantalla? Esta bien el de contraste a luz de dia? Muchas gracias

  10. Hello
    Enhorabuena por el artículo: descripción/precisión y profesionalidad. Se agradece tanta ayuda.
    Me ha permitido decantarme claramente hacia 255s dejando a un lado 745.

    Me surgen dos dudas:
    – natación en pisicna si, no? He leído varias especificaciones, pero me quería asegurar porque claramente se potencia la opción tri/aguas abiertas.
    – colores del “s” solo gris y rosa? Has encontrado algún sitio donde hayan otras opciones (negro/turquesa).

    GRACIAS de verdad
    ENHORABUENA por tu trabajo/dedicación


    1. Sí, natación tanto en piscina como en aguas abiertas.

      De momento los colores son los que hay, y además depende de si es con música o no.

      Gracias Yolanda.

  11. Buenas, gran artículo y esperando al análisis completo.

    Estoy muy interesado en renovar mi fr235 ya que he empezado con el tri y se me queda bastante corto. Tengo algunas dudas ya que el fr745 se puede encontrar por 300€.

    Referente a la potencia en carrera, se puede incluir como una métrica mas en la pantalla de datos (como el %fr max) y poder entrenar por zonas, o sólo se puede ver la potencia instantánea con la app de stryd.

    Otra duda que tenía es si la potencia con la banda hrm es fiable en comparación con el stryd. Ya que comprar una cosa u otra el precio cambia bastante. Y por ultimo se puede utilizar la banda de tickr x de wahoo. Ya que es bastante cómoda y también funciona para el análisis en carrera.

    Continúa con los análisis del material y videos. Nos ayuda bastante a todos.

    A salute!

    1. Si quieres utilizar Stryd tienes que seguir utilizando la app, por el momento no es compatible con sensores de potencia externa de forma nativa.

      En cuanto a los datos de potencia con el sensor de Garmin, son «fiables» en cuanto a su propio algoritmo, pero diferentes a lo que muestran otros fabricantes.

      Para potencia sólo son compatibles los sensores de Garmin, no puedes utilizar el de Wahoo.

  12. Hola Eduardo, muchas gracias por estas previews tan completas. Una pregunta, por favor, tengo el 255 y me gustaría personalizar las pantallas de datos de los entrenos avanzados que configuro en Garmin Connect. No he visto forma de hacerlo, ¿no se puede? ¿Hay alguna manera de incluir el ritmo medio en vuelta? Si pulso ‘down’ durante el entreno, ¿me mostrará otras pantallas con ese dato? El ritmo instantáneo no me resulta muy útil, la verdad, porque va de 5 en 5 segundos. ¡Muchas gracias!

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