Kenkou Zenrakei Suieibu Umishou - S01

Kaname Okiura is a student at Prefectoral Umineko Shougyou High, or "Umishou" for short. He joins the school’s swimming club to learn how to swim, but the club is full of oddballs-none of whom seem capable of teaching him. Then, a cheerful, carefree girl named Amuro Ninagawa transfers in from Okinawa and joins the club. Her incredible speed underwater and unconventional swimming style, along with her habit of swimming nude-which naturally draws the attention of the boys-shocks the entire club, especially Okiura. She reminds him of a mermaid-like creature he glimpsed once as a child.