Pocket-lint is supported by its readers. When you buy through links on our site, we may earn an affiliate commission. Learn more

(Pocket-lint) - While the smartwatch revolution seems to have stumbled, fitness and sports devices have grown and adapted. In many ways companies like Garmin have surpassed the smartwatch generation by focusing on features that add value, rather than adding distraction.

Take the Garmin 645 Music: it introduces music to the Garmin family, along with mobile payments, smartphone notifications and customisations, sitting on a platform that not only tracks your activity, but excels in delivering your stats. It's as smart as any smartwatch, and then some.

A compact design for universal appeal

  • Gorilla Glass 3 display, 1.2-inch, 240 x 240 pixel resolution
  • 42.5mm face, 13.5mm thickness, 42.2g weight
  • Changeable silicone strap
  • Stainless steel bezel
  • 5ATM waterproofing 

The first Forerunner devices - the first to put GPS tracking on your wrist - were huge. Even as technology progressed, Garmin has faced the challenge of how to make devices small enough to widen their appeal - especially for those with smaller wrists. 

Advancing technology brings a lot of these things and in the 645 Music you have a watch that's still sporty in design, but much slimmer than models of a few years back. It's also smaller than the 700 and 900 series devices and that's garnered some complimentary remarks when we've been wearing the 645 Music. It's a good size, without being excessive.

Pocket-lintGarmin Forerunner 645 Music image 6

The metal ring encircling the 645's display provides a highlight, borrowing stylings from the likes of the Vivoactive 3; indeed, there's huge crossover between Garmin's "sport" and "lifestyle" models, the biggest difference being that Forerunner uses buttons and Vivoactive is touchscreen based. It's hard to use touchscreen interfaces when running, thus we prefer the buttons.

Elsewhere the 645's body is polycarbonate, with quick release straps, giving some potential to change them if you wish. There are a few different colour versions, with the rose gold giving highlights in place of the stainless steel in our review model.

Let's talk about music

  • Bluetooth connection to headphones
  • Up to 500 song storage
  • Only supports music sideloading 

Music on the go was quickly adopted by smartwatches and has been a feature of some running watches, like the TomTom Spark, for a few years. It's also a feature offered by the Fitbit Ionic, so it was inevitable that Garmin would find a solution. Indeed, it's very welcome, letting you listen to music via Bluetooth headphones without the need for a phone. 

What you'll have to do first, however, is get the music onto your watch. And that's still a fiddle, requiring connection to your PC to transfer your own music. At launch Garmin had said that it would support Deezer, but that hasn't happened to date. It's still in progress, but it's not currently a feature, so there's no sensible playlist syncing.

Pocket-lintGarmin Forerunner 645 Music image 11

Connecting to Bluetooth headphones is pretty easy, though, just as you would add any other accessory from the Garmin universe, you just have to put your headphones into pairing mode and search for them. We found it reliable, connecting to the excellent Libratone Track+. Together they make a great combination for running. 

Control of music isn't the most logical, sitting in the normal run of widget screens, but you'll have to manually add the screen to your activity screens if you want to easily control music when running. We found ourselves using the headphone controls for volume, pausing and skipping, which tells you all you need to know about how accessible music controls are via the watch. It's currently not the best experience out there.

Features: It's all about the data

  • Heart rate, GPS, altitude, cadence, motion
  • Running, cycling, swimming and other sports
  • Huge ecosystem of sensors

In recent years we've seen Garmin move from being a sports tracking-only device, to a lifestyle device. No longer do people strap on their watch only to go for a run, they might wear it all the time. As such, it's no surprise that the Garmin Forerunner 645 Music will give you steps and sleep tracking, it will offer you movement reminders, and it will help you on the way to achieve your weekly intensity goals. 

Pocket-lintGarmin Forerunner 645 Music image 2

All-day heart-rate tracking is offered too, so you can keep an eye on your average heart rate thanks to the optical heart-rate sensor on the back. We've found the Elevate heart-rate monitor to return accurate results in line with other Garmin devices, hitting the highs and the averages we'd expect to see.

One of Garmin's inherent advantages is its wide compatibility with other Garmin sensors - that might be an old heart-rate sensor from a previous watch, a cadence sensor on your bike or any number of others - within the company's ecosystem. It's very easy to add sensors to get more accurate or more specific data, which is great for those who decide they want to add accurate swim or cycle tracking to this watch. If you do have a chest strap, that will unlock some features, like the heart-rate variability stress test, which needs the accuracy of a chest strap to give you a measure.

The watch also offers a barometric altimeter, compass, thermometer and GPS, as well as motion sensors, to gather a whole lot more data. That's where you went, the temperature, altitude change, distance, speed, your cadence, steps and performance condition. There's basic navigation and support for routes, as well as the ability to track your way back to the start of your run (great for running new routes or when on your travels) as well as LiveTrack through a connected phone (perfect for letting loved ones see where you are on those long rides).

Pocket-lintscreens image 4

What all this data amounts to is a set of metrics to track your sports training, performance and progress. It's more than more rivals offer, too. There are some insights offered through the Garmin Connect app, you get all the graphs to track your performance over time, but in some cases it's data that a coach might use. Want to increase your running speed? It might be that focusing on increasing your cadence is what you have to target.

There are some elements we really like, like the training status. This looks at the training volume and intensity and gives you an idea of where you are. You want to be in the "productive" stages, so you know your exercise is promoting gains. If the intensity drops, your status will change to unproductive. This goes hand-in-hand with the recovery time. Hit a hard session and Garmin will tell you for how long you should rest. With overtraining being a concern, this might help you avoid it - but it does just work on averages and it doesn't know your individual physiology or your training aims.

This feature set isn't unique to the 645 Music. In fact, most of these stats are offered by a number of Forerunner devices. And therein lies one of the problems this watch faces: if it's sports stats that you're after, then the older Forerunner 735XT is some £100 cheaper (losing Garmin Pay and Music), but just as effective when it comes to sports.

Pocket-lintScreens image 2

In terms of sports support, the mainstays are swimming , running and cycling - there's no golf support (see the higher-level Forerunner, Fenix or Approach devices for that), but you can set it track gym workouts, create custom sports and completely customise the information screens you're served. For example, we took the Garmin Forerunner 645 on the Three Peaks Challenge, using the "walking" settings, with an added navigation display.

Garmin Forerunner 645 Music battery life

  • Realistic 5 day battery life 

With so much data being captured, there's a lot for this Garmin to use its energy on. The cited life on paper is a week, but that's a little generous in our experience. Throw in three decent runs with headphones connected for your music and you're looking at more like 5 days of life. 

In terms of the actual event time, you'll get about 10-12 hours of activity tracking before you might start worrying about battery life (without music). We tested this on the Three Peaks, clocking up 10 hours of walking, with about 25 per cent remaining - so we wanted to charge before the 5 hours on the final mountain.

Pocket-lintGarmin Forerunner 645 Music image 4

So how does this compare to other devices? The battery life isn't as long-lasting as the Garmin Forerunner 935. The flagship 9-series device is larger and therefore its longevity proves true. The Forerunner 645 Music betters the Fitbit Ionic by lasting longer, despite similar specs. Compared to regular smartwatches like the Apple Watch or Wear OS devices, the Garmin more than doubles the life.

Garmin Connect, app and smartwatch functions

  • Great app for data
  • Smartwatch notifications and smart replies on Android
  • Garmin Pay not widely supported by UK banks 

All your data is gathered into Garmin Connect (which will run on Android or iPhone) to give you access to your data on the move. The app also passes data back to the watch, letting you see things like calendar appointments, weather and notifications.

Pocket-lintScreens image 1

Garmin Connect has evolved in recent years to be a lot more lifestyle - you can track all sorts of data, not just that coming from the watch - and it's customisable with easy-to-view stats. The website equivalent is, frankly, a bit of a mess compared to Polar Flow or Fitbit's Dashboard, but we like the smartphone app a lot. 

You can share data with other services too - with native Strava support so you can keep track of your Strava segments - and there's the option to easily share your stats, putting your data on a map or photo for social media (#garmin).

Syncing and connectivity is good and moving your device to a new phone doesn't prove problematic, neither does using multiple Garmin devices - and TrueUp will sync across devices, so if you're using separate devices for cycling and running then you'll have combined training status, rather than one ignoring the other (both devices need to be compatible).

Best Fitbit fitness tracker 2021: Which Fitbit is right for you?

There's plenty of customisation and while the selection of apps might not match those natively offered by Wear OS or Watch OS (Google and Apple), we don't really feel that these wearables are about apps.

Garmin Pay is also supported in the 645, meaning contactless payments when on the move. That's great for those who might run and then fancy getting a milkshake on the walk home as a cooldown. In the UK, however, the supported banks list is rather barren and if you want to use Garmin Pay then you might have to open an account especially for that reason. US users are better served.

Notifications offer smart replies for those on Android, as well as full customisation of what notifications you do or don't want. There's no voice control like you might get on some smart watches, but you're not left in the dark: Garmin isn't just about sports, it's just better at sports. 


The Garmin Forerunner 645 Music breaks new ground for Garmin, offering a wider feature set than previous devices, including music (although there's a slightly cheaper version without music if you prefer).

Sports performance is really what this watch is about. Although it will keep up with other smartwatches with notifications and functions, it surpasses them in sports data. That's supported by the kind of battery life that other smartwatches can only dream about, meaning you can have a long weekend away, connected, while tracking activity, and not have to pack a charger.

In terms of device design, the 645 reduces bezel and bulk for a more slimline sports device. It's still a bulky design with its five buttons (see the Vivoactive 3 Music if you don't want all those buttons), but it's comfortable to wear, and waterproof enough for swimming and dealing with a sweat soaking.

However, it's the headline music sell that could be better; currently it's really a case of sideloading music from your PC, rather than easy playlist syncing, so until its Deezer future is realised the 645 is limited in this department.

The bottom line is that the Garmin Forerunner 645 Music promises a lot, but the music and pay additions don't really deliver... yet. You can get a comparable sports experience from Garmin's cheaper watches. Until the music offering gets more compelling or the price drops, you might be better off picking another model, despite all the positive benefits as outlined throughout this review.

Alternatives to consider

Pocket-lintAlternatives image 2

Garmin Forerunner 735XT

Aimed at the multi-sport athlete, the Forerunner 735XT was one of the first devices from Garmin to put heart rate on the wrist. So it's a little old - and the user interface isn't as logical as the more recent devices - but in terms of technical sports tracking, it's up there with the best. The appeal is that its age means it pretty cheap these days.

Pocket-lintalternatives image 1

Fitbit Ionic

Fitbit's offering carries with it a lot of lifestyle appeal, while offering many of the same top-line functions as the Forerunner 645 Music. It offers Fitbit Pay, music on the move - with Deezer playlist syncing - and will track your steps, sleep, heart rate, and all your sports performance. There's more of a lifestyle angle though, with Garmin offering more and better data, as well as better battery life than Fitbit's watch.

Writing by Chris Hall. Originally published on 27 July 2018.