Marathon Swims 2023 is now open for entries

Marathon Swims 2023 is back at the London Aquatics Centre, inviting swimmers to take on the ultimate challenge – a Marathon 10K.

Marathon Swims, London’s marathon of swimming, returns to the London Aquatics Centre at Queen Elizabeth Olympic Park on Saturday 11 November 2023. Following sell-out events in 2017, 2018, 2019 and 2022, the event is back to challenge swimmers to take on the ultimate swimming challenge: a Marathon 10K.

The event is supported by two exciting new partnerships. Alzheimer’s Society has been named as the official charity partner, while Cassie Patten – British freestyle swimmer and coach who won the bronze in the 10K open-water event at the 2008 Beijing Olympics, and who regularly writes for Outdoor Swimmer – is the official training partner with her swimming coaching company WaveCrest Swimming.

What is Marathon Swims?

Marathon Swims is swimming’s own marathon. Every city in the world has a (running) marathon, half marathon and triathlon. Now, with Marathon Swims, cities can host their own swimming marathon.

The swimming marathon distance first came to prominence at the Beijing Olympic Games in 2008. The 10K marathon swim has been a key element in the Olympic schedule ever since with spectacular races in the Serpentine (London 2012) and at Copacabana Beach (Rio 2016).

Marathon Swims has redefined the 10K challenge as an indoor, pool-based Marathon 10K, Half Marathon 5K and a 1K Challenge distance event. The event has a unique format, where participants swim in each 50m lane at the London Aquatics Centre, completing 1km, before having a rest in the ‘transition zone’. You can watch an explainer, below.

Can you swim the distance?

If the full 10K distance feels too much of a stretch, the event also includes a 5K Half Marathon, 1K Challenge and the Team 10K, where teams of two take on the 10K distance. All entries fundraising for Alzheimer’s Society are offered at half price, and your place will be guaranteed in any challenge distance.

“We’re very proud to bring this event back once again to the Pool of Champions. The event is a London 2012 legacy event, so we’re thrilled to be back in this wonderful Olympic venue,” said Marathon Swims’ Founder Diccon Loy. “Our aim was to create the ‘London marathon’ of swimming and if we can fundraise for Alzheimer’s Society, a small fraction of what the London Marathon generates, we’d be delighted.”

Marathon Swims 2023 will be held on Saturday 11 November 2023 at the London Aquatics Centre on Queen Elizabeth Olympic Park. Entry is now open, with entries decided by ballot (ends 23:45 Wednesday 10 May 2023). Follow @MarathonSwims for more. Browse more upcoming events and challenges with the Outdoor Swimmer events finder.

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Jo is the Gear Editor for Outdoor Swimmer and also writes news and features for the website. A keen open water swimmer and long-distance walker, she loves seeking out lakes and lidos close to her home in the Mendip Hills, Somerset. She is the author of The Slow Traveller, editor and founder of independent magazine, Ernest, and has previously tested outdoor clothing and kit for BBC Countryfile Magazine, BBC Focus and Ernest Journal.