An Ironman is a long-distance triathlon race organized by the World Triathlon Corporation (WTC) . The full event consists of a 2.4-mile swim, a 112-mile bike ride, and a 26.2-mile run, all to be completed in a time limit of 17 hours with cut off times for each leg. Participants who finish within the time parameters achieve the prestigious title of Ironman. The term Ironman has now become synonymous with races of this distance. In the triathlon community, an Ironman is someone who has completed a race of the appropriate distance, whether or not it falls under the aegis of WTC.

The Ironman triathlon was first held in Hawaii on February 18, 1978, with 15 participants. The name "Ironman" was derived from a statement made regarding the winner of what was clearly going to be a grueling triathlon race: "Whoever finishes first, we shall call him the Iron Man". Today, there are hundreds of Ironman races around the globe, and thousands of people compete in an Ironman event every year.

An Ironman is not for the faint-hearted and is widely considered to be the gold standard of endurance triathlon racing. The fastest Ironman times in the world are 7:21 for men and 8:18 for women, but the average male Ironman finish time is 12:27, and the average female Ironman finish time is 13:16. Anyone can do an Ironman as long as they are prepared to put in the hours of dedicated long-course training.