Garmin Forerunner 165 vs. Garmin Forerunner 55: Key differences explained

Garmin's release of the Forerunner 165 has added a much-needed budget option to its lineup, but the Forerunner 55 is still the cheapest way to get a running watch from the company on your wrist. 

The latter is now a little long in the tooth, having released back in 2021, and could well be updated at some point in 2024, but those operating with a budget of around $150-300 now have a very hard decision to make.

In this comparison guide, we'll cross-examine all the key areas you should consider before buying one of these two running watches. Let's dive in.

• In-depth Garmin Forerunner 165 review
• Full test: Garmin Forerunner 55 review

Price and versions

• Garmin Forerunner 165: $249 / £249 (standard), $299 / £289 (Music)
• Garmin Forerunner 55: £199 (standard)

While you have just one version of the FR55, there are instead two to pick between if you begin looking at the FR165: the standard model and a slightly pricier FR165 Music. 

There are no differences between the pair other than support for music storage and offline playback for services like Spotify, Amazon Music, and Deezer.

At present, we think the standard FR165 offers the best value. It's definitely worth upgrading by $50/£40 for the screen tech alone - and it also has plenty more features than the FR55. Things start to get a little pricey if you choose the Music edition, however, and could then start to consider upgrading to the Forerunner 265.

Design and display

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• Forerunner 165: Plastic case, 1.2-inch AMOLED display
• Forerunner 55: Plastic case, 1.04-inch transflective MIP display

Both of these running watch lines are lightweight and designed to be unobtrusive on the wrist - and they feel relatively identical during daily wear and runs. 

The FR55 clocks the scales at 37g, while the FR165 is a tad heavier at 39g. This isn't noticeable at all, and you can't really go wrong with the slightly bigger FR165 (43 x 43 x 11.6mm) or FR55 (42 x 42 x 11.6 mm) when it comes to sizing. 

Garmin does offer different case sizes for some of its pricier watches - like the Fenix 7 Pro or Epix Pro - but that's not an option you have with either of these lines. 

Thankfully, 42mm/43mm is a pretty unisex case size - even if it's a bit more suited to small and average wrists.

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Really, the big difference between these two isn't in the shell of the design - it's in the display technology.

The FR165 boasts a larger, vibrant AMOLED display that can provide super clarity even in sunlight, while the FR55 features a smaller, monochrome transflective memory-in-pixel (MIP) display that's more efficient. 

As we just mentioned, we think the AMOLED display is far superior to MIP screens and worthy of an upgrade in itself. It isn't as battery efficient (more on that below), but it's worth it.

Running features

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• Forerunner 165: GPS, HR monitoring, Garmin Coach, PacePro, Race Widget, Daily Suggested Workouts, Running Dynamics, VO2 Max, Training Effect, HRV Status
• Forerunner 55: GPS, HR monitoring, Garmin Coach, PacePro, Race Predictor, Daily Suggested Workouts

Garmin is very careful about how it spaces out the features available on its running watches. For the most part, it all hangs together - ensuring you always get a little bit more functionality for your money and that value is retained across the many Forerunner models. 

Given these two models are at the bottom of the chain, you can expect the two most basic feature sets, with the FR165 just having the edge when it comes to features for runners.

What we would say, though, is that these are two very run-focused watches. Unlike pricier models such as the Forerunner 965, these two aren't designed to be full-time training companions for the likes of triathletes - and that means tools like Training Status, Training Readiness, Endurance Score, and Hill Score aren't available.

Instead, both the FR165 and FR55 focus on the basics. There's single-frequency GPS tracking - which will give you great accuracy, despite not being top-tier - and heart rate tracking from Garmin's Elevate V4 sensor.

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This sensor is last-gen tech, but it's still as good as most optical HR sensors on the market - and the same featured in the FR265 and FR965. 

This is where things split off, however. While the FR165 has room for Training Effect (the measurement of which system your workout developed), the Race Widget (and its adaptive training suggestions), and Garmin's Running Dynamics analysis, the FR55 instead sticks to support for Garmin Coach plans and very basic post-run analysis.

Again, we think the upgrades are worth it for most people - though those who just want a very basic start-stop tracker that accurately logs distance and HR will find it with the FR55.

Health, sleep and smart features

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• Forerunner 165: Sleep tracking (advanced), nap detection, stress monitoring, Body Battery (advanced), smartphone notifications, music support, Pulse Ox 
• Forerunner 55: Sleep tracking (basic), stress monitoring, Body Battery (basic), smartphone notifications

While these two don't look too different when it comes to this area, there are a few subtle differences - and the advantage naturally goes to the newer FR165 in this respect.

This is particularly prevalent in areas like sleep tracking and Body Battery energy monitoring, as they've been given a bit of an update in presentation (both on-watch and in Garmin Connect) and what's tracked. 

While the FR165 offers sleep scores and nap detection, for example, the FR55 will simply log your hours and assess your sleep stages. You just get that bit extra on the more expensive model.

Both watches feature Body Battery, too, but the FR165 now shows a breakdown of the specific effect activities, rest periods and sleep tracking had on your score - complete with a neat little graph.

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Neither is very complete when it comes to smart features or health tracking, mind - and that's to be expected with two very run-focused devices.

Again, the FR165 is slightly more advanced. It boasts Garmin's SpO2 Pulse Ox tech, allowing you to take spot readings or set up background monitoring during sleep (or throughout the whole day if you don't mind the battery drain this causes), but this is about the extent of its health features.

It also, as we've mentioned, has the option of music storage if you want to pay the premium, whereas the FR55 is limited to media control only when connected to your iOS/Android device.

Battery life

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• Forerunner 165: 11 days (watch mode), 19 hours (GPS)
• Forerunner 55: 14 days (watch mode), 20 hours (GPS)

The FR55's sole victory comes in the battery life department - though, in reality, this is only really a win on paper. 

It may be able to last a few more days than the FR165, but the trade-offs (primarily the AMOLED display, but also the features on board) just aren't really worth it. 

Frankly, 11 days is still more than enough for a running watch - and there's also a negligible difference when it comes to efficiency when tracking via GPS. 

We should say that having the FR165 in 'watch mode' will ensure the always-on display is off, however. And, in our testing, we've found that turning this display mode on (alongside max brightness) will see the battery life dip down to around a week.

Still very respectable, even at half of the FR55's capacity in AOD mode.

Verdict: Which is best?

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Knowing which is the best option for you is all about understanding your budget and needs. With that in mind, we recommend the following.

Choose the Forerunner 165 if:

• You want a colorful and detailed display
• You need slightly more running metrics
• You value music storage and offline playback
• Your budget can stretch closer to $300/£300

Choose the Forerunner 55 if:

• You want better battery life
• You don't value run-tracking insights
• You want the most budget-friendly Garmin running watch

Ultimately, both of these watches are very capable and reliable running companions. The FR165 offers a bit more for intermediates or advanced beginners, while the FR55 provides excellent value for those just starting. Choose the watch that aligns best with your priorities and budget.