Swimrun is a multi-sport adventure race, consisting of swimming and running multiple stages in one long continuous race. Unlike triathlon, there is no transition phase between stages, the same clothing is worn throughout. Any equipment must be carried for the whole event. The races are typically held with the swimming legs in open water, and the running stages on trails. The use of multiple swimming and running legs distinguishes this sport from Aquathlon and Biathle.
Swimrun events are structured as racing from a starting point to a finish line through a course with at least two swim and two run sections. The race distances can vary. To increase safety, the carrying of flotation devices is encouraged, particularly to support the feet as wearing running shoes can cause the feet to drag.
The equipment allowed includes pull buoys, swim paddles, shoes, wet-suit, tether, pressure bandage, whistle, and foldable cups/flasks.
Swimrun originated in Sweden. An island to island race in Sweden in 2002, which started as a challenge between friends, has turned into the internationally recognized ÖtillÖ (Island to island) Swimrun World Championship. It is also labeled as one of the world's toughest one-day adventure races.
Swimrun is gaining in popularity, with hundreds of races organized annually around the world.
- Aquathlon — a continuous race involving swimming followed by running. It is a similar format to biathle, though over longer distances.
- Biathle — like aquathlon, consists of swimming and running as part of a single race, though they are of much shorter distances and are of higher speeds, compared to that of aquathlon races.
- Aquabike — a shortened version of triathlon, with no running leg. Athletes swim followed by cycling.
- Triathlon — a continuous event involving swimming, cycling, and running.
- Duathlon — similar to triathlon, running first, then cycling, then running again
- Quadrathlon — consists of swimming, kayaking, cycling, and running.
- Triathle — a shortened version of the Modern Pentathlon, athletes compete in shooting, swimming and running events as a part of a single race.
- Swimming — the sport of propelling oneself through water using the limbs.