The sport of aquathlon consists of a continuous, two-stage race involving swimming followed by running. The International Triathlon Union (ITU) and its member federation organizations sanction competitions and govern the sport. An aquathlon is also called an "aquathon." The ITU and USA Triathlon sanctioning organizations generally use the term aquathlon.
Aquathlons have been around in various forms since the early 20th century in ocean lifeguard competitions. The National Surf Lifesaving Association of America, formed in 1965, held its first national competition that year and the events included a run-swim-run. The modern international standard lifeguard distance is 400 meter run - 400 meter swim - 200 meter run.
Modern pentathlon is similar to an aquathlon in that both include swimming and running. But swimming and cross-country running are only two of the five events which make up the modern pentathlon, and these are held as distinct, noncontiguous events. Within the penthathlon sport the term biathle is also used for (training) races comprising swimming and running. These however contain distance stemming from pentathlon races, for instance 200m swimming 3 km running.
Aquathlon in general follows triathlon distances. For instance 1 km swim - 5 km run at the 2004 world champs in Queenstown, or 2.5 km run - 1 km swim - 2.5 km run in Lausanne 2006. However, distances vary depending upon the race venue and race director.
Aquathlons are most similar to triathlons, with the key difference being the lack of a cycle leg. Another sport derived from triathlon is duathlon, which combines cycling and running but has omitted the swimming part. Holding an aquathlon rather than a triathlon can be an attractive option for a race director because: