The swimming competitions at the 2004 Summer Olympics in Athens took place from 14 to 21 August 2004 at the Athens Olympic Aquatic Centre in Marousi. It featured 32 events, a total of 937 swimmers from 152 nations, and the program's changes instituted in the previous Games, including notably the three-phase format for all short-distance races.
The men's 200 metre freestyle event at the 2004 Summer Olympics was contested at the Olympic Aquatic Centre of the Athens Olympic Sports Complex in Athens, Greece. The event took place on 15 and 16 August. There were 59 competitors from 53 nations, with each nation having up to two swimmers.
The men's 100 metre breaststroke event at the 2004 Summer Olympics was contested at the Olympic Aquatic Centre of the Athens Olympic Sports Complex in Athens, Greece on August 14 and 15.
The men's 4×100 metre freestyle relay took place on 15 August at the Olympic Aquatic Centre of the Athens Olympic Sports Complex in Athens, Greece.
The men's 100 metre butterfly event at the 2004 Olympic Games was contested at the Olympic Aquatic Centre of the Athens Olympic Sports Complex in Athens, Greece on August 19 and 20.
The men's 200 metre butterfly event at the 2004 Olympic Games was contested at the Olympic Aquatic Centre of the Athens Olympic Sports Complex in Athens, Greece on August 16 and 17.
The men's 200 metre individual medley event at the 2004 Olympic Games was contested at the Olympic Aquatic Centre of the Athens Olympic Sports Complex in Athens, Greece on August 18 and 19.
Ian Lowell Crocker is an American former competition swimmer, five-time Olympic medalist, and former world record-holder. During his career, he set world records in the 50- and 100-meter butterfly and the 100-meter freestyle. He has won a total of twenty-one medals in major international competition, spanning the Olympics, the FINA World Aquatics Championships, and the Pan Pacific Swimming Championships. He coached for many years at the Western Hills Athletic Club and has helped coach the Longhorns swim camp in 2019 as well as other years. Since Spring of 2022 when the new facility opened, Crocker coaches at the Western Aquatics and Social Club at the Eanes Independent School District Aquatics center.
Erik K. Vendt is an American former competition swimmer. He won a silver medal at the 2000 Summer Olympics and the 2004 Summer Olympics in the 400-meter individual medley. At the 2008 Summer Olympics, Vendt won a gold medal as a member of the U.S. 4×200-meter freestyle relay team, swimming in the preliminary heats of the relay event.
Ryan Steven Lochte is an American professional swimmer and 12-time Olympic medalist. Along with Natalie Coughlin, Dara Torres, and Jenny Thompson, he is the second-most decorated swimmer in Olympic history measured by total number of medals, behind only Michael Phelps. Lochte's seven individual Olympic medals rank second in history in men's swimming, tied for second among all Olympic swimmers. He currently holds the world records in the 200-meter individual medley. As part of the American teams, he also holds the world record in the 4×200-meter freestyle and 4×100-meter freestyle (mixed) relay.
Oussama "Ous" Mellouli is a Tunisian swimmer who competes in the freestyle and medley events. He is a three-time Olympic medalist, is an African record holder, and trains with the USC Trojans team based at the University of Southern California, where he studied as a computer science undergraduate and swam collegiately.
The men's 4 × 200 metre freestyle relay event at the 2008 Olympic Games took place on 12–13 August at the Beijing National Aquatics Center in Beijing, China.
The men's 4 × 100 metre medley relay event at the 2008 Olympic Games took place on 15 and 17 August at the Beijing National Aquatics Center in Beijing, China.
The men's 200 metre freestyle event at the 2008 Olympic Games took place on 10–12 August at the Beijing National Aquatics Center in Beijing, China. There were 58 competitors from 50 nations.
The men's 400 metre individual medley event at the 2008 Olympic Games took place on 9–10 August at the Beijing National Aquatics Center in Beijing, China.
Allison Rodgers Schmitt is an American competition swimmer who specializes in freestyle events. She is a four-time Olympian and a ten-time Olympic medalist.
David Walters, also known as Dave Walters, is an American former competition swimmer, Olympic gold medalist, and world record-holder in the 4x200 meter freestyler relay. At the 2008 Summer Olympics, Walters earned a gold medal by swimming in the heats of the 4×200-meter freestyle relay. As part of the American team, he also formerly held the world record in the 4×100-meter medley relay. Walters is also a seven-time medalist at the World Aquatics Championships.
Michael Fred Phelps II is an American former competitive swimmer. He is the most successful and most decorated Olympian of all time with a total of 28 medals. Phelps also holds the all-time records for Olympic gold medals (23), Olympic gold medals in individual events (13), and Olympic medals in individual events (16). When Phelps won eight gold medals at the 2008 Beijing Games, he broke fellow American swimmer Mark Spitz's 1972 record of seven first-place finishes at any single Olympic Games. At the 2004 Summer Olympics in Athens, Phelps already tied the record of eight medals of any color at a single Games by winning six gold and two bronze medals. At the 2012 Summer Olympics in London, Phelps won four gold and two silver medals, and at the 2016 Summer Olympics in Rio de Janeiro, he won five gold medals and one silver. This made him the most successful athlete of the Games for the fourth Olympics in a row.
Jiro Miki is a Japanese former swimmer, who specialized in individual medley events. He is a two-time Olympian, a double Olympic finalist in both 200 and 400 m individual medley, and a silver medalist at the 2002 Asian Games in Busan, South Korea.
Guntars Deičmans is a Latvian former swimmer, who specialized in individual medley events. He is a 2004 Olympian, and a multiple-time Latvian champion and record holder in the same stroke.
