Fitness fans: you can finally leave your smartphone at home.

Garmin has been churning out fantastic sports watches for years, but it's taken until now for one to get music playback. The 645 Music takes the basic Forerunner formula and adds a splash of Bluetooth, so all you have to do is hook up a pair of headphones - then you're good to go with your tunes, without lugging a phone around as well.

We strapped one on at CES in Las Vegas to see whether it'll be music to your ears, or if Garmin should have stuck with the sound of silence.

DESIGN & BUILD

The 645 is significantly smaller than the rest of the Forerunner range, and is practically dwarfed by the Fenix 5. Not that this is a bad thing, mind: the chunky Fenix makes it obvious you're into fitness, but the 645 doesn't scream "ask me anything about pre-workout carb loading".

You can go incognito with one of these on your wrist, wearing it every day and only activating the exercise tracking once you're out of the office. The silver metal finish around the watch face really adds to the premium feel, too.

We were impressed with how light it felt, with little of the heft you'd find on a high-end Forerunner or Fenix.

It uses the same 20mm straps as Garmin's Vivoactive range, with quick release pins that make it easy to swap 'em out for different colours, if you like to accessorize. These straps have always stayed secure on our wrists, even while flailing our arms about like a mad person when out running - the 645 is in safe hands here.

Finally, Garmin hasn't tried to mix things up with a touchscreen - you get good old fashioned buttons, which are much better suited to sports watches. There's still a backlight, activated with a push, which softly illuminates the screen just enough to see it clearly at night.

MUSIC

For a first effort, Garmin has done a great job of adding music support to the 645. You pair up your Bluetooth headphones just like you would a chest strap, through the watch’s menu screen.

About 3.5GB of the built-in 4GB storage is available for storing music, which can be loaded onto the watch through Garmin Express on a PC or Mac. Don’t have a lot of MP3 files lying around any more? The 645 Music will support iHeartRadio and Deezer at launch, with your playlists automatically syncing and refreshing whenever you get within Wi-Fi range.

It doesn’t seem like you can share tracks directly from a smartphone just yet, but Garmin is listening to customer feedback and may change that at a later date.

The Music screen appears alongside all the other ConnectIQ widgets, with playback controls arranged in a straightforward, circular layout that’s easy to navigate with the hardware buttons.

The one thing we can’t vouch for is connectivity. Turns out Garmin doesn’t like it when you try running with their samples still firmly strapped to your wrist. We’ll have to wait until a full review to see if dropouts are a concern, but our demo went without a hitch, so things are looking good.

FEATURES

The 645 Music is sort of like a “greatest hits” of Garmin’s recent watches, with notable extras like contactless NFC payments, Connect IQ app support, and a barometric altimeter. You’d have had to pick up a triathlon version or a Fenix to get those kinds of features before.

In fact, the only things missing from the 645 are advanced navigation, and multisport / open water modes. Otherwise pretty much every Fenix feature is present and correct. That means you're getting one of the most comprehensive runner's watches around, in a much smaller package than before.

The interface is essentially identical, with buttons jumping back and forth between menus, individual screens for heart rate and lap times. It wasn't broken before, so we're glad Garmin hasn't tried to "fix" it. Everything felt as responsive as a Fenix, too.

The usual heart rate sensor, built-in GPS and non-workout activity tracking are all present and correct, and the whole thing is 5ATM waterproof for pool swimming or wearing in the shower.

Garmin Forerunner 645 Music initial verdict

Music support has been a long time coming, and Garmin seems to have delivered in a way that stays true to its simple, straightforward approach to fitness watches.

The Forerunner 645 Music isn't flashy, doesn't complicate things with a touchscreen, and keeps everything we loved about the more expensive Fenix series - only now you can listen to your tunes when you're exercising. Which can only be a good thing.

We love the small size, too - it won't look huge on tiny wrists, but equally doesn't look ridiculous if your arms are more like tree trunks.

If you're after a fitness watch you can wear 24/7, this looks like it might be ideal. We can't wait to give it a full review a little closer to launch.