Waterboys (ウォーターボーイズ, Wōtā Bōizu) is a 2001 Japanese comedy film written and directed by Shinobu Yaguchi, about five boys who start a synchronized swimming team at their high school. The film stars Satoshi Tsumabuki (Suzuki, the leader of the team), Hiroshi Tamaki (Sato), Akifumi Miura (Ohta), Koen Kondo (Kanazawa), Takatoshi Kaneko (Saotome) and Naoto Takenaka (the dolphin trainer).

The film was a success in Japan, and was nominated for eight prizes at the Japan Academy Prize, winning awards for 'Best Newcomer' and 'Best Music Score'. A spin-off television series entered its third season in 2005.