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 (3.86 km) swim, a 112-mile (180.25 km) bicycle ride and a marathon 26.2-mile (42.2 km) run, raced in that order and without a break.he name Ironman Triathlon is also associated with the original Ironman triathlon which is now the Ironman World Championship. Held in Kailua-Kona, the world championship has been held annually in Hawaii since 1978 (with an additional race in 1982) and is preceded by a series of qualifying Ironman events.