A new formula for open water racing: the 3k Knockout

World Aquatics have found a new way to add drama to open water swimming

(Image credit: Istvan Derencsenyi/ World Aquatics)

Did you see the new 3km Open Water Knockout competition, which debuted at the 2025 World Aquatics Championships in Singapore in July? It’s my new favourite open water format to watch – and I wish there were a version for masters swimmers like me.

Here’s how it works.

1. Bring together around 60 of the world’s fastest open water swimmers. Then split them into two equal-sized groups at random and send them off on a 1500m swim in two heats, separated by a couple of minutes.
2. Take the first 10 finishers from each heat, allow them 10 minutes to rest and recover and put them into a semi-final where they race over 1km.
3. Now take the top 10 finishers from the semi-final and, after a further 10-minute rest, put them into a 500m final.

The whole thing takes about an hour. It’s fast, brutal, compelling and fun. I hope it attracts more viewers to open water events and tempts more pool swimmers to try open water.

The format was first trialled at the 2023 World Junior Open Water Championships in Portugal, followed by a pilot on the World Aquatics Open Water World Cup circuit. Singapore 2025 marked its first appearance at the senior world level. I hope it won’t be the last.

Built for TV?

Open water fans will have noticed that the 25km marathon swim has been dropped from the World Championship programme. While some long-distance specialists will lament its demise, it’s easy to see the commercial logic. A 25km swim is costly to put on and attracts fewer swimmers and viewers.

In contrast, the 3km Knockout brings suspense, drama and intense competition. If it was designed with television viewers in mind, I think it’s succeeded.

Will it become an Olympic Event? David Betlehem from Hungary, who finished second, certainly hopes so:

“I hope this format is going to be in the Olympics in 2032. If yes, maybe I’m going to come back. At 28, I’m going to retire but I will come back if this event is in the Olympics,” he said.

Tactical dogfight

For the swimmers, every second counts and there is little margin for error. At the same time as battling for places in subsequent rounds, they need to conserve enough energy to be able to race – and to finish with a sprint.

As the rounds progress, the distance to the first turning buoy decreases. In the longer 5km and 10km events, drafting to conserve energy is a huge advantage. In the 3km Knockout, there are clear benefits to reaching the buoy first and getting a clean turn. In some cases, a quick turn allowed the leaders to put a gap of several metres over the following pack.

And the winners are…

In the men’s event, Olympic and world champion Florian Wellbrock (GER) delivered a masterclass in pacing and positioning, powering through all three rounds to take gold in the final sprint (he also collected gold in the open water relay, the 5km and the 10km). Hungary’s Dávid Betlehem claimed silver after using his powerful underwater kick off the start to put himself in a great position. France’s Marc-Antoine Olivier bronze.

In the women’s race, Japan’s Ichika Kajimoto, surged from mid-pack to a brilliant finish, despite losing her swimming cap. Italy’s Ginevra Taddeucci was just behind for silver, while Moesha Johnson (AUS) and Bettina Fábián (HUN) tied for bronze in a dramatic finish.

The other winners are World Aquatics, for creating this innovative and dramatic open water format, and us – open water fans. We now have a new event to watch.

Attractive for pool swimmers?

While all the top finishers in Singapore were open water specialists, I can’t help but wonder if the new format and shorter swims will attract more pool swimmers to open water. Surely Leon Marchand has the versatility to crush his format? And Katie Ledecky has the raw speed. The question is, could they cope with the physicality and tactical nature of it? After all, the beauty of racing outside is that you need both speed and open water skills. I’d love to see more pool specialists in open water.

Where to watch

If you missed the World Championships, don’t worry. Replays of the knockout and all other open water events are available to stream free on Eurovision Sport. If you haven’t yet watched the 3km knockout, I recommend it. It’s open water swimming at its best.