Swimming, though not part of Ancient Olympics, was a popular sport. Swimming competitions were held in Europe and Japan before first AD. In modern Olympics, swimming was introduced in 1896 itself. Since then, it has been a popular event in the Olympics.

Swimming Records in Olympics - Men

Ian Thorpe of Australia holds Olympic records for men's 200 meter freestyle swimming and men's 400 meter freestyle swimming. He made the record in men's 200 meter freestyle swimming with a timing of 1:44.71 seconds in the 2004 Athens Summer Games while the record in the men's 400 meter freestyle swimming was made in the 2000 Sydney Summer Games. The timing was 3:40.59 seconds.
Grant Hackett of Australia holds the current Olympic record in men's 1500 meter freestyle swimming event. He made the record in the 2004 Athens Summer Games with the timing of 14:43.40 seconds.
Alexander Popov of Russia holds the current Olympic record in men's 50 meter freestyle swimming competition. His timing was. The record was made in the 1992 Barcelona Summer Games with the timing of 21.91 seconds.
Pieter Van Den Hoogenband of the Netherlands holds the current Olympic record in men's 100 meter freestyle swimming competition. The record was made in the 2000 Sydney Summer Games with the timing of 47.84 seconds.
Aaron Peirsol of USA holds the Olympic record in men's 100 meter and 200 meter backstroke swimming events. Timing achieved in the 100 meter backstroke swimming event was 53.45 seconds while in 200 meter backstroke swimming, the time taken was 1:54.95 seconds. Both records were made in 2004 Athens Games.
Brendan Hansen of USA holds the record of men's 100 meter breaststroke in the 2004 Athens Summer Games. The timing was 1:00.01 seconds.
Kosuke Kitajima of Japan holds the Olympic record in men's 200 meter breaststroke swimming event. The record was made by in the 2004 Athens Summer Games and the timing was 2:09.44 seconds.
Michael Phelps of USA holds the record of men's 100 meter butterfly swimming event with the timing was 51.25 seconds. The event was 2004 Athens Olympics. He also finished the 200 meter individual medley in 1:57.14 seconds in same event creating a new Olympic record.
Australian team of Ian Thorpe, Michael Klim, Todd Pearson and Bill Kirby holds the Olympic record in men's 4X200 meter freestyle relay. With the timing of 7:07.05 seconds, the record was made in 2000 Sydney Olympics.
A team of the USA comprising Aaron Peirsol, Brenden Hansen, Ian Crocker and Jason Lezak holds the Olympic record in men's 4X 100 meter medley relay. With a timing of 3:30.68 seconds, the record was made in the 2004 Athens Summer Olympics.
South African team of Roland Schoeman, Lyndon Ferns, Darian Townsend and Ryk Neethling holds the Olympic record in men's 4X100 meter freestyle relay swimming event. The record, which has the timing of 3:13.17 seconds, was made in the 2004 Athens Summer Olympics.