One Water Race, billed as one of the world’s most demanding endurance events, will return to Sweden’s Stockholm archipelago on August 19-21, 2025.
Now in its fourth year, the race features 10 mixed-gender teams taking on a 250km course that blends trail running, open-water swimming and orienteering. Among the line-up is the first-ever British team.
The non-stop race takes between 50–60 hours to complete and includes a US$100,000 prize purse. Beyond its physical challenges, the event aims to raise awareness of environmental issues, with a focus on ocean conservation.
The 2025 edition will again be supported by a 65+ hour live broadcast produced by NEP Group – known for its work on the Champions League and Olympics – and distributed internationally via A.S.O., the media company behind the Tour de France and Dakar Rally. The broadcast is expected to reach more than 190 TV markets.
“One Water Race is a global media property as much as it is an athletic event,” said Thomas Ogander, founder of One Water Race. “It’s slow TV with real-time drama — a unique way to tell stories of human capacity and environmental urgency.”
This year’s event will also introduce biometric tracking for the first time, in collaboration with the Swedish School of Sport and Health Sciences (GIH). Athletes will wear sensors to monitor real-time physiological and cognitive data during the race.
“We study how the body and brain react under prolonged extreme stress — both to expand the boundaries of sports science and to explore how these insights can be applied in real-world markets,” said Dr Marcus Moberg, Associate Professor at GIH.
One Water Race blends extreme endurance sport with a message of environmental advocacy. Its format is designed to test both physical and mental resilience, with athletes navigating the archipelago’s rugged terrain and cold waters under their own steam.
