Since the launch of the Nintendo Music app in October 2024, Nintendo has consistently been expanding the service (free for Nintendo Switch Online members) with more soundtracks from their extensive library of games.
Today’s update includes an hour and a half of music from the 2007 Nintendo DS classic, The Legend of Zelda: Phantom Hourglass, with 80 total tracks added. The curated playlists this time around are for Overworld, Battles, and People of the Great Sea, alongside the usual Extended-Playback Collection, which allows you to listen to select tracks with a seamless loop.
Nintendo Music is available now for iOS and Android devices from their respective app stores.

Spirit Tracks has the better OST of the two DS Zeldas but this is still a good addition. A little surprising this was added before Twilight Princess though.