swimmate

plural swimmates

1. A person or animal with which one swims.

   “Don’t pet them around the blowhole”: Dolphin Quest participants meet their swimmates

   1989 November 27, Eugene Linden, “An Uneasy Dip with the Dolphins”, in Time, volume 134, number 22, page 80

   2 more examples

   As they ready for the big splash, Claudia [Kolb] speaks for her Olympic swimmates when she says, “I’ve learned much more than just being able to win. I can accept challenges and I can accept defeats. It’s all a part of the game.”

   1968 October, “Olympic Splashdown”, in American Girl, Girl Scouts of the U.S.A., page 37

   Sharing a peaceful co-existence with his swimmates, Mark [Spitz] went on to beat twenty-eight world records by the end of his 1972 pre-Olympic trials in Chicago . . .[…]

   1973 January, Barbara Graustark, “The Re-Making Of Mark Spitz”, in Circus, volume 7, number 4, page 42