Paolo Francesco Radmilovic was a Welsh water polo player and competitive swimmer. Radmilovic had Croatian and Irish origins. He represented Great Britain at four editions of Summer Olympics. He won four Olympic titles in a 22-year Olympic career. He won four gold medals across three successive Olympic Games, a record which stood for a Great Britain Olympic athlete until broken by Sir Steve Redgrave when he won his fifth gold medal at Sydney in 2000. In 1928, he became the first person to compete for Britain at five Olympic Games, a record that would remain until surpassed by fencer Bill Hoskyns in 1976.

At the 1908 Summer Olympics, a water polo tournament was contested.