Nao Serizawa

A third-year student who serves as the manager of the Iwatobi Junior High School Swim Club.

Responsible for overseeing Haruka and the others. Specializes in backstroke. Highly trusted by his same-year peer, Natsuya.

Has an eye condition and cannot compete in matches during junior high, hence serving as the manager.

In the third season, he advances to a university in Tokyo to study sports medicine. He worked part-time as a coach teaching children to swim at a community pool. Although he quit due to moving, he reunites with Haruka and the others through Makoto, who became the new coach.