Middle school freshmen Haruka and Makoto join the school swim team, and have to join forces with their new teammates to win.
| Actor | Role |
|---|---|
 Koki UchiyamaIkuya Kirishima (voice) | Ikuya Kirishima (voice) |
 Nobunaga ShimazakiHaruka Nanase (voice) | Haruka Nanase (voice) |
 Tatsuhisa SuzukiMakoto Tachibana (voice) | Makoto Tachibana (voice) |
 Satomi SatoNagisa Hazuki (voice) | Nagisa Hazuki (voice) |
 Kenji NojimaNatsuya Kirishima (voice) | Natsuya Kirishima (voice) |
 Mamoru MiyanoRin Matsuoka (voice) | Rin Matsuoka (voice) |
 Yoko HikasaRei Ryuugazaki (voice) | Rei Ryuugazaki (voice) |
 Chihiro SuzukiKisumi Shigino (voice) | Kisumi Shigino (voice) |
 Aoi YuukiSousuke Yamazaki (voice) | Sousuke Yamazaki (voice) |
 Satoshi HinoNao Serizawa (voice) | Nao Serizawa (voice) |
 Toshiyuki ToyonagaAsahi Shiina (voice) | Asahi Shiina (voice) |