Apple Watch has enough space to store 200 songs locally on the device. It’s a small amount, but helpful for those rare moments when your iPhone is out of reach or left at home.
Sync a playlist from your iPhone
To copy music across from your iPhone, attach your Apple Watch to its charger, then open the Apple Watch app on your iPhone and select the Music option. Next, tap Synced Playlist and select the one you’d like to store on Apple Watch. The tracks will now begin to copy across from your iPhone to Apple Watch.
Play music stored locally on Apple Watch
If you’d like to play the music stored on your Apple Watch, instead of the music on your iPhone, then open the Music app on Apple Watch and press firmly on the screen. Next, tap Source and select Apple Watch. You’ll need to use a paired device to hear the music. These might include a pair of Bluetooth headphones, Apple TV or a hearing aid. To choose a paired device, tap Settings, the tap on the device of choice.