The Swimming competition at the 6th Pan American Games was held in Cali, Colombia during the Games' run in 1971. It consisted of 29 long course (50 m) events: 15 for males and 14 for females. A world record was beaten in this edition of the Games, by the U.S. 4 x 200 m freestyle men's relay. The victory of Canada in the women's 4x100m medley marked the first time that the U.S. lost the gold in a relay event, at the Pan American Games.