Open water swimming is the most arduous of aquatic disciplines. The swimmers not only have the long distances to contend with, they also have to deal with a multitude of elements such as the weather, water currents and sometimes even aquatic wildlife.
Open water swimming was included in the FINA World Championships for the first time in 1991 in Perth. There are events for men and women, over 5km, 10km and 25km distances. There is also a (mixed) team competition.
The 5km event was introduced in 1998, and the 10km event introduced in 2001.