If you are a premium Spotify user, you can listen to 13 million tracks from your Android device. Here's how to sync playlists and listen to them offline without internet connection on your Android..
Step 1: Launch the Spotify app and click on the “Edit offline playlists” button.
Step 2: Tap the checkbox next to the playlist you want to sync. Spotify will start syncing the tracks from your device..
Step 3: When you open the synced playlist, you will notice a green icon next to each track.
Step 4: To make Spotify only stream the songs offline, tap “More” from the menu at the bottom and then click the checkbox next to “Offline”..
Step 5: Streaming songs from your synced playlist is now available offline.
Offline mode is very useful for listening to music on the plane or in places where there is no internet connection. It's also a good way to cut down on cellular data usage by syncing your playlists over Wi-Fi and listening to them offline.
Note: The number of tracks you can sync is limited to 3333 songs, in addition, you will be asked to sign in to your Spotify account once a month to verify that you are a member.