Swimming is a water based sport governed by the Fédération Internationale de Natation (FINA).

Swimming has been recorded since prehistoric times; the earliest recording of swimming dates back to Stone Age paintings from around 7,000 years ago. Written references date from 2000 BC. Some of the earliest references to swimming include the Gilgamesh, the Iliad, the Odyssey, the Bible, Beowulf, and other sagas. In 1578, Nikolaus Wynmann, a German professor of languages, wrote the first swimming book, The Swimmer or A Dialogue on the Art of Swimming (Der Schwimmer oder ein Zweigespräch über die Schwimmkunst). Competitive swimming in Europe started around 1800, mostly using breaststroke. In 1873, John Arthur Trudgen introduced the trudgen to Western swimming competitions, after copying the front crawl used by Native Americans. Due to a British dislike of splashing, Trudgen employed a scissor kick instead of the front crawl's flutter kick. Swimming was part of the first modern Olympic games in 1896 in Athens. In 1902 Richmond Cavill introduced the front crawl to the Western world. In 1908, the world swimming association, Fédération Internationale de Natation (FINA), was formed. Butterfly was developed in the 1930s and was at first a variant of breaststroke, until it was accepted as a separate style in 1952.

Swimming may refer to:

Sport (or, in the United States, sports) is all forms of competitive physical activity which, through casual or organised participation, aim to use, maintain or improve physical fitness and provide entertainment to participants. Hundreds of sports exist, from those requiring only two participants, through to those with hundreds of simultaneous participants, either in teams or competing as individuals.

Sport is generally recognised as activities which are based in physical athleticism or physical dexterity, with the largest major competitions such as the Olympic Games admitting only sports meeting this definition, and other organisations such as the Council of Europe using definitions precluding activities without a physical element from classification as sports. However, a number of competitive, but non-physical, activities claim recognition as mind sports. The International Olympic Committee (through ARISF) recognises both chess and bridge as bona fide sports, and SportAccord, the international sports federation association, recognises five non-physical sports, although limits the amount of mind games which can be admitted as sports.