Open water swimming has a brand-new event, and it’s already shaking things up on the world stage.

The 3km Knockout Sprint made its debut at both the 2025 World Aquatics Open Water Swimming World Cups and the World Aquatics Championships in Singapore, bringing a fast-paced, all-or-nothing edge to a sport traditionally defined by endurance.

It’s being hailed as the next big thing in open water, a made-for-spectators format that keeps the action sharp, decisive, and thrilling right to the final stroke.

How it works

The knockout sprint is a three-stage race designed to whittle the field down in quick succession:

• Heat (1.5km): The starting field is split into heats, with the fastest 10 from each going through.
• Semi-final (1km): A shorter, punchier swim where only the top 10 advance.
• Final (500m): A flat-out sprint for glory.

In the space of an hour, the field is cut down from dozens of hopefuls to a single winner,  making it as brutal as it is spectacular.

From trial to prime time

First trialled at the 2023 World Junior Championships in Italy, the format quickly proved its worth. By mid-2025, it was in the World Cup program in Ibiza, and by July, it had taken centre stage at the World Championships in Singapore’s Sentosa Island.

For swimmers, it’s a whole new tactical challenge: managing energy across multiple races, deciding when to go hard, and keeping enough in the tank for the all-important final. For fans, it’s a dream, quick-fire racing with no dead water.

Singapore showdowns

The first-ever World Championship knockout crowns were decided in style:

• Florian Wellbrock (Germany) claimed the men’s title, completing a golden treble with wins in the 5km, 10km, and 3km sprint.
• Ichika Kajimoto (Japan) stormed home in the women’s final, with Italy’s Ginevra Taddeucci taking silver and a rare dead-heat for bronze between Australia’s Moesha Johnson and Hungary’s Bettina Fábián.

It was a fitting debut, world champions decided in front of big crowds, with nail-biting finishes and plenty of colour on shore.

Hitting Australian waters

The knockout format hasn’t just been a global experiment – it’s already made a splash at home. The 2025 Australian Open Water Cup in Darwin featured the sprint-style event as part of its program, giving local swimmers and fans a front-row seat to the fast, tactical format.

And it’s not stopping there. The Noosa Summer Swim Festival, hosted by World Series Swims, will also showcase the knockout sprint, putting it on the calendar alongside some of Australia’s most popular open water challenges.

With both elite and mass-participation events embracing the format, the knockout sprint is quickly becoming more than a headline act – it’s cementing itself as part of the Australian open water scene.

Why it matters

The knockout sprint isn’t just a novelty. It’s seen as an answer to the loss of the 25km event from the international program, giving swimmers more chances to race and teams more depth at major meets.

It also ticks all the boxes for modern sport: fast, dynamic, and built for spectators both on site and watching from afar. Importantly, its arrival in Australia – from Darwin to Noosa – shows that it’s not only an international showcase but a format being embraced at every level of the sport, bringing fresh energy to local waters.

As one official put it, “only the fastest survives”, and in open water, that’s about as pure as it gets.