Will my Bluetooth earbuds work with my Apple Watch even if I don't have my phone with me? I want to listen to music while I am running but don't want to bring my phone with me. Can I just pair the bluetooth earbuds that I use now with my phone and take my watch running?
You can listen to music on the Apple Watch without your iPhone. In this answer, you'll learn how to sync a playlist and pair your bluetooth headphones.

Make a music playlist

You can keep one music playlist on your Apple Watch at a time.
Audiobooks and podcasts aren't compatible.


On your iPhone, go to the Music app.
Tap My Music > Playlists > New.
Give your playlist a name, and then tap Add Songs.
Search or tap to find songs, artists, or albums to add. 
When you find something that you'd like to add, tap "+".
After you add the item, tap Done. You can then search for more music to add. 
When you're done adding music, tap Done to save your playlist. (A)


Sync your playlist


Set your Apple Watch on its charger and make sure the device is charging.
On your iPhone, go to Settings > Bluetooth. Make sure Bluetooth is turned on.
From the Apple Watch app on your iPhone, tap My Watch > Music > Synced Playlist.
Tap the playlist you want to sync to your Apple Watch. When a message next to your playlist says Sync Pending, your playlist will
begin syncing from your iPhone to your Apple Watch.
Wait until the sync is finished before using your Apple Watch. To see the sync progress, open the Apple Watch app on your iPhone and tap
Music. You might need to download any music stored in the cloud, such
as music from Apple Music or iTunes Match, to your iPhone before you
can sync it with the Watch. (B)




Pair Bluetooth headphones with your Apple Watch

To listen to music on your Apple Watch, you'll need to connect to
Bluetooth headphones:


Put your Bluetooth headphones in pairing mode using the instructions that came with them. You might need to enter a passkey or
PIN (Personal Identification Number).
On your Apple Watch, go to Settings > Bluetooth. Your Apple Watch will search for nearby Bluetooth devices.
Choose your Bluetooth headphones and enter a passkey or PIN if asked.


Listen to the playlist on your Apple Watch

After pairing your headphones, you can listen to your synced playlist
without an iPhone:


From the Home screen on your Apple Watch, tap the Music app.
Force Touch, then tap Source > Apple Watch.
Tap play to listen to your playlist.