Garmin Forerunner 55 vs. Forerunner 255 – Which Watch Is Right for You?

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If you don’t have your own smartwatch yet or you’re considering replacing the one you currently have, chances are you’re looking into Garmin’s offerings.

They’re a big name for a reason, and no matter where you are in your running journey, there’s a watch to suit your needs.

You may be wondering about the Garmin Forerunner 55 vs. Forerunner 255. Garmin watches’ names can get confusing, as many of them are similar.

Both the 55 and the 255 are relatively new on the market, but they’re quite different in terms of features and usability. Depending on your level, it’s quite likely that you’ll strongly favor one over the other once you know what they offer.

Let’s have a closer look at these two watches, their similarities and differences, and which one would be best for certain kinds of athletes. It’s worth noting that we’re using the regular non-music Forerunner 255 for this particular review!

Main Differences

In terms of the Garmin Forerunner 55 vs. Forerunner 255, the differences are quite stark. They’re definitely aimed at two different kinds of athletes.

The Forerunner 255 is the newer of the two watch models and replaced the Forerunner 245. The Forerunner 55 has been around for a bit longer, and it replaced the Forerunner 45.

Probably the biggest difference is that the Forerunner 55 is in the entry-level category while the Forerunner 255 is more advanced.

This naturally leads to another large difference—the price. While the entry-level 55 will cost you about $200 at this time, the more detailed 255 costs around $350.

It goes without saying that there’s quite a difference in features and functionality, considering who the two watches are aimed at. Let’s have a look at the rest of the differences in more detail.

Summary of Each Watch

Forerunner 55

The Garmin Forerunner 55 is ideal for your first running watch. Even if you’re experienced, it’s a great choice if you want an easy, no-fuss watch.

It does a great job of tracking your important metrics, whether you’re running or doing some cardio-based cross-training. It also offers basic recovery stats and some swimming functions.

Forerunner 255

The Forerunner 255 is also great for first-time runners, especially if you’re a data geek and love to use your numbers to improve. It tracks a good bit more data than the 55, bumping it up above entry-level.

It’s also an excellent choice for triathletes. As well as running features, the 255 has more advanced cycling and swimming functions, so you can track every aspect of your sport.

Size and Display

Forerunner 55

The Forerunner 55 is available in just one size, 42 mm. Its full size is 42 x 42 x 11.6 mm, which is a good size for most wrists and doesn’t look bulky even on a lady’s wrist. The regular silicone strap can fit wrists between 126 and 203 mm in circumference.

It’s also quite lightweight, weighing just 37 grams with the silicone strap. With this on your wrist, you won’t feel weighed down or less aerodynamic.

The display size is 26.3 mm, which is a decent size, and the screen is full-color with a resolution of 208 x 208 pixels.

Forerunner 255

The Forerunner 255 is available in your choice of 2 sizes: 41 mm and 46 mm. To give you an idea, the larger case measures 45.6 x 45.6 x 12.9 mm and fits wrists between 130 to 205 mm in circumference. It weighs 49 grams.

The display size is 33 mm and has a slightly higher resolution than the 55, at 260 x 260 pixels. It also has a full-color screen.

Those whose wrists are smaller or want less bulk on their wrist can choose the more petite 41 mm case design, which also weighs just a little less.

Battery

Forerunner 55

The Forerunner 55 can last up to 14 days in smartwatch-only mode. In GPS mode, you can get up to 20 hours of use before you need to recharge.

Forerunner 255

The Forerunner 255 can also last up to 14 days in smartwatch-only mode. In GPS mode, you can expect 30 hours of use before the battery dies, a good 10 hours more than the 55.

In UltraTrac mode, you can get up to 54 hours of use. But if you go for the music-version of the 255, the battery will drain much quicker.

Hardware

Forerunner 55

The Forerunner 55 uses the Garmin Elevate V3 heart rate sensor, which isn’t the newest one Garmin has released but does the job. It doesn’t offer SPO2 levels, though.

Aside from the heart rate monitor, you’ll find GPS, GLONASS, Galileo navigation systems, and an accelerometer. You should note that the 55 does not come with a thermometer, compass, or altimeter.

Forerunner 255

The Forerunner 255 is equipped with Garmin’s Elevate V4 sensor, which is their latest one. It also measures blood oxygen levels.

This watch features GPS, GLONASS, Galileo, and multi-frequency positioning. It also has an accelerometer, barometric altimeter, compass, gyroscope, and thermometer. This better equips you for hiking or trail running as you can measure elevation, check your direction, and other features.

Maps and Navigation

Forerunner 55

The Forerunner 55 features your standard GPS tracking, with GPS, GLONASS, and Galileo capabilities. There are no navigation features on this watch, so it’s not ideal for hiking or trail running, where you need to follow the GPS.

Forerunner 255

The Forerunner 255 features dual-frequency GPS functions, allowing the watch to use two different satellite frequencies at the same time for improved accuracy. It’s the first of Garmin’s mid-range watches to feature this kind of navigation.

You can upload specific courses to the Forerunner 255 and follow them as you run. You won’t be able to navigate to a specific location in real-time, though; you have to have preloaded the course onto the watch.

It also has a “back to start” function, which can guide you back to your course if you happen to get lost as you’re running.

Activities

Forerunner 55

The Forerunner 55 offers running activity profiles, cycling activity profiles, swimming activity profiles, and a small group of others.

For running, you can choose from:

  • Running
  • Treadmill Running
  • Track Running
  • Indoor Track Running
  • Virtual Running

For cycling, you can choose from:

  • Biking
  • Indoor Biking

And for swimming, you have Pool Swimming but no open water swimming. The other choices you have are:

  • Elliptical Training
  • Stair Stepping
  • HIIT
  • Pilates
  • Yoga

There are no outdoor activity or strength training profiles on this watch. It’s mostly geared towards running.

Forerunner 255

The Forerunner 255 offers more activity profiles than the 55 and multiple profiles for outdoor sports or strength training. It’s more well-rounded than the 55 in terms of sporting options.

For running, you can choose from:

  • Running
  • Outdoor Track Running
  • Treadmill Running
  • Indoor Track Running
  • Trail Running
  • Virtual Running
  • Ultra Running

For cycling, you can choose from:

  • Biking
  • Indoor Biking
  • Mountain Biking
  • eBiking
  • eMountain Biking

For swimming, you have:

  • Pool Swimming
  • Open Water Swimming

You also have multiple outdoor recreation profiles:

  • Hiking
  • Skiing
  • Snowboarding
  • XC Classic Skiing
  • Stand-Up Paddleboarding
  • Rowing

And multiple fitness-related profiles:

  • Strength
  • HIIT
  • Cardio and Elliptical Training
  • Stair Stepping
  • Floor Climbing
  • Indoor Rowing
  • Pilates
  • Yoga

Overall, the Forerunner 255 is a much-more feature-rich watch than the 55 in terms of choice of activity.

Training Aids

Both the 55 and the 255 offer heart rate zone training, recovery time calculation, interval training, advanced workouts, downloadable training plans, and VO2 max during running. However, there are some very noticeable differences.

Forerunner 55

The Forerunner 55 is a basic running watch. You’ll be able to track your usual pace, distance, time, and cadence when you’re running. It also offers PacePro strategies, Race Predictor, and built-in run workouts.

It’s also compatible with running foot pods, as well as cycling cadence and speed sensors. It’s most feature-rich in terms of swimming, offering metrics like pool swim metrics like stroke count, SWOLF, stroke detection, drill logging, and swim efficiency.

Forerunner 255

If training aids are what you’re after, the Forerunner 255 is by far the better option. For running, it includes handy advanced metrics like stride length, ground contact time, vertical oscillation, lactate threshold, and running power, provided you have a compatible accessory.

You can also connect a cycling power meter to get data like your lap maximum power, Functional Threshold Power, and compatibility with a variety of Varia accessories.

You’ll get pacing alerts, critical swim speed, and pool swim workouts in the pool. You can also use a compatible heart rate monitor for more accurate HR monitoring.

You also have a course-specific and weather-specific race predictor, heart rate variability, training load, training effect, readiness, and course guidance.

Health Monitoring

The Forerunner 55 and 255 offer similar capabilities in terms of health tracking. Both offer second-by-second heart rate monitoring, respiration rate, abnormal heart rate alerts, and a daily resting heart rate monitor.

Other common features include:

  • Fitness Age
  • Body Battery Energy Monitor
  • All-Day Stress Tracking
  • Relaxation Reminders
  • Advanced Sleep Tracking
  • Hydration Reminders
  • Women’s Health Tracking

The Forerunner 55 also offers a pulse oximeter, sleep score and sleep insights, and a health snapshot.

Music

The Forerunner 55 lacks any music capabilities. You can buy a “Music” version of the 255, but you should note that the regular version doesn’t come with music capabilities.

The music version is $50 more expensive than the non-music 255. It stores up to 500 songs directly on the watch. When listening, you can use Bluetooth earphones, stream music from various platforms, and store downloaded playlists for offline listening.

Accessories

Both watches are compatible with many Garmin accessories, including quick-release wristbands and Garmin charging cables.

Both also have Bluetooth and ANT+ capabilities, so you should be able to connect them to a variety of external accessories, but it’s wise to check first.

Forerunner 55

The Forerunner 55 is compatible with the Garmin HRM-Pro, HRM-Pro Plus, and HRM-Dual. It also works with Garmin’s bike Speed Sensor 2, Cadence Sensor 2, and the wristwatch bike mount.

Forerunner 255

The Forerunner 255 is also compatible with the HRM-Pro, Pro-Plus, and Dual. It also works with the HRM-Run and Garmin’s soft strap and elastic straps. You can also attach it to the bicycle mounting kit.

In terms of Garmin sensors, the 255 works seamlessly with the Garmin Running Dynamics Pod, Garmin Tempe, the Speed Sensor 2, and Cadence Sensor 2.

It’s also compatible with specific external devices, including Rally and Vector pedal-based power meters and a wide range of Varia accessories.

You can also connect your Garmin Forerunner 255 to a smart bike trainer if you prefer to train indoors.

Other Features

Forerunner 55

Interestingly, although the Forerunner 55 doesn’t offer any outdoor activity profiles, it does feature area calculation and a hunting/fishing calculator through the Garmin Connect IQ app, both of which the 255 doesn’t have.

Forerunner 255

The Forerunner 255 offers some interesting miscellaneous features, including:

  • VIRB Camera Remote, allowing you to control a VIRB action cam from up to 10 meters away
  • Garmin Pay, so you don’t have to carry your wallet or cash with you
  • The Garmin Connect Challenges App, for more challenging workouts
  • On-screen workout animations and muscle maps, plus rep counting

Price

At the time of writing, the Forerunner 55 sells for $200 on the Garmin website, while the Forerunner 255 is going for $350.

Both are well-priced for a Garmin device. The 55 is undoubtedly in the entry-level range, but the 255 is a mid-range choice.

However, the Forerunner 55 offers more bang for your buck in terms of value. It has many of the same features as the Forerunner 255, without in-depth metrics.

If you aren’t using your smartwatch for detailed analysis in order to improve your performance, the Forerunner 55 is the better choice.

Summary

If you’re still undecided about choosing the Garmin Forerunner 55 vs. Forerunner 255, here’s a quick summary.

The Forerunner 55 has some great features, but it’s best for entry-level runners who want something simple, easy to use, and budget-friendly.

The Forerunner 255 features more advanced analytics that would be handy for more experienced runners who want to use their data to improve their performance. It’s still relatively well-priced for a Garmin but lacks some of the fancy features of high-end Garmins.

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AUTHOR

Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.