35978d12_Zelda___Majora_s_Mask____Songs__Where_to_play
[How to play] Epona's Song [How to learn] To learn this song, Link has to finish Romani's archery game in under two minutes before the night of the first day at Romani Ranch. You'd think that Link would remember this song from his days back in Hyrule.... Seems to be a very important tune, if you ask me. [Where to play] 
Play this song anywhere in Termina Field, Romani Ranch, Milk Road or the entrances to the swamp, bay and canyon. Anywhere else, Epona cannot reach you. Another possibility for a use of this song is to play it for Gossip Stone since it will release a bottle-able fairy upon hearing it.
The Legend of Zelda : Majora's Mask -- Songs
Where to play