Oma Oma ~

Kenkou Zenrakei Suieibu Umishou – Season 1

It's the Kantou prefecture swimming tournament, and the Umisho swim club is there. After doing poorly in the preliminaries due to a bet, the girl's team pours things on in the middle. In the relay race, the team discovers another team is cheating when they use a song to help the swimmer along.