The Ironman Triathlon is an annual long-distance race that is organized by the World Triathlon Corporation and held in Hawaii. The race consists of three ordered events: a 2.4 mile swim, a 112 mile bike race and a 26.2 mile marathon run. The event begins at 7 a.m. and competitors are required to cross the finish line by midnight.

The idea for the Ironman race originated from the 1977 Oahu Perimeter Relay. Members of the 5-person teams often debated whether runners or swimmers were in better shape. The bike race was also added when U.S. Navy Commander John Collins argued that cyclists were more athletic. The first Ironman Triathlon was help on February 18, 1978, in Honolulu, Hawaii, and was created in an attempt to settle the debate. The event quickly became famous for its harsh conditions and length. The triathlon was repeated several times with extensive television coverage. The first to finish the race would be declared an "Iron Man." However, the event's registered trademark reflects how finishing is an achievement in itself: "Swim 2.4 miles! Bike 112 miles! Run 26.2 miles! Brag for the rest of your life."

The Ironman World Championship format remains mostly unchanged despite the events' switch from spring to fall. The current record holders include Luc Van Lierde from Belgium whose winning time was 8 hours 4 minutes and 8 seconds in 1996, and Chrissie Wellington from Great Britain who set the women's course record in 2009. She had a winning time of 8 hours 54 minutes and 2 seconds.