An Ironman Triathlon is one of a series of long-distance triathlon races organized by the World Triathlon Corporation (WTC), consisting of a 2.4-mile (3.9 km) swim, a 112-mile (180.2 km) bicycle ride and a marathon 26.22-mile (42.2 km) run completed in that order, a total of 140.6 miles (226.3 km). It is widely considered one of the most difficult one-day sporting events in the world.
An Ironman 70.3, also known as a Half Ironman, is one of a series of long-distance triathlon races organized by the World Triathlon Corporation (WTC). The “70.3” refers to the total distance in miles (113.0 km) covered in the race, consisting of a 1.2-mile (1.9 km) swim, a 56-mile (90 km) bike ride, and a 13.1-mile (21.1 km) run. Each distance of the swim, bike, and run segments is half the distance of that segment in an Ironman Triathlon.