Free!(2013)

The story of this anime is about a boy named Haruka Nanase who always loves water and swimming. Before graduating from elementary school, he joins his school's swimming team and participates in these competitions with three other teammates named Tachibana Makoto, Hazuki Nagisa, and Matsuka Rin. They win this competition and after this competition, each of them goes their own way. Time passes and they enter high school. One day, Rin appears in front of Haruko and invites her to a competition. Haruko is defeated and when she sees Rin's incredible strength, she goes and finds her friends again and brings a new member named Ryugazaki Rei to the swimming team and forms the Iwatobi school swimming team with the goal of defeating Rin.