The traditional triathlon includes three sports: biking, swimming, and running. However, not all triathlons are the same. Sponsors offer triathlon races in four distances and degrees of difficulty.
- The short-distance Sprint triathlon involves a 0.5-mile swim, a 15-mile bike ride, and a 3-mile run. Frequently chosen by beginners, the sprint is the most popular distance.
- The Olympic triathlon, which follows international Olympic guidelines, is generally considered the traditional triathlon, with swimming, biking, and running distances, respectively, of 0.93 miles, 24.8 miles, and 6.2 miles.
- The full Ironman triathlon, the iconic competition, requires athletes to swim 1.2 miles, bike 112 miles, and run 26 miles (a marathon). Usually, only professional athletes attempt a full Ironman.
- A Half Ironman includes a swim of 1.2 miles, a bike ride of 56 miles, and a run of 13 miles.
The triathlon has also evolved various spinoffs, such as the off-road triathlon, the indoor triathlon, the winter triathlon, and the duathlon, in which one of the legs is omitted. The Aquabike duathlon leaves out the run, and the Aquathlon leaves out the biking.