> Part of the Kantai Collection series( http://www.batoto.net/search?name=Kantai%20Collection&name_cond=c&genres=;e9&genre_cond=and )

Ogawa Tomoo, a high-school boy, who can't figure out why his classmate, Oomori Yuka, likes him so much. Unlike him, she's friendly, upbeat, excels at sports and is one of the most popular students in the school. Tomoo doesn't understand why someone so attractive would be interested in someone like himself. He decides to push Yuka away for her own good but her persistence eventually pays off and he can not help but be attracted to her.

From ryColaa:
Our hero, who doesn't know how to swim, joins his school swimming club and begins to learn from their star swimmer who loves swimming more than anything. Good thing she's cute and nice to boot!