Waterboys

Suzuki is a high school student who aspires to become a great swimmer, however, he is the only person in the school’s swimming team. Soon, a beautiful new swimming teacher starts work at the high school. Dozens of boys decide to join the swimming team, but when they realize that she teaches synchronized swimming, all but Suzuki and four other boys drop out. The teacher soon leaves work on maternity leave, and for some time the team is on hiatus. However, when Suzuki watches a dolphin show he decides to ask the dolphin trainer to be their coach. —Wikipedia