The aquatic sport of swimming is based on the human act of swimming, that is, locomotion in water by self propulsion, with the goal of completing a given distance in the shortest amount of time. There are also swimming competitions for endurance or precedence rather than speed, such as crossing the English Channel or some other stretch of open water.

Competitive swimming consist of four strokes: butterfly, breaststroke, freestyle (or front crawl), and backstroke. When all four strokes are done during a race, it is called medley swimming (otherwise known as the individual medley, or I.M.).