What is a race involving swimming followed by running called?

An aquathlon is a multisport race consisting of continuous run and swim elements. Competitors complete a swim immediately followed by a run over various distances. Athletes compete for fastest overall course completion, including the time transitioning between the disciplines.

Aquathlon is one of a family of endurance based multisport races, which gained popularity from triathlon and various independent races in the second half of the twenty century. Modern aquathlon is viewed as a discipline of triathlon as standard races cover the same distances as triathlon but without the cycling leg. As such the sport is governed by International Triathlon Union who organise the world championships each year.

The modern roots of aquathlon can be traced to life guarding races in Australia, in the 1950s. Races would consist of a run along a beach, swim out to sea round a buoy and swim back to the beach, get out and then run back along the beach. By the 1960s the idea had spread to California in the United States, becoming popular with runners and swimmers.