What is Open Water Swimathon?

You. The open water. A brand new challenge. Open Water Swimathon.

Open Water Swimathon participants will have the opportunity to participate as individuals (1.5K, 2.5K or 5K) or as a team (1.5K or 5K), providing the perfect challenge for both experienced open water swimmers, and those transferring from the pool to the open water for the first time.

We’re delighted to announce that Cancer Research UK and Marie Curie are uniting as partners for Open Water Swimathon to raise as much money as possible for two causes close to the nation’s hearts. This is your chance to fundraise for both incredible causes.

And remember… you are not getting in the open water alone! From the moment you sign-up, you will receive communications from the Open Water Swimathon team, helping you and guiding you in the lead-up to the event!


Not close enough to any of the host venues? Offered sessions not suiting your schedule? Distances not quite right for you? There are lots of reasons why you might be unable to attend an Open Water Swimathon organised session, but that does not mean that you cannot take part.

The SimplySwim challenge has been designed for those that can’t attend an organised session but don't want to miss out.

To offer you more flexibility with your open water swimming challenge, take on SimplySwim and choose your own venue and swimming times.

You will still be able to raise money for a fantastic cause, and of course to challenge the whole family, your friends and your colleagues to take part as well.

In a nutshell, SimplySwim rules are:

  • You can swim one of the set challenges (Individual 5k, Individual 2.5k, Individual 1.5k, Team 5k, Team 1.5k or your own set distance).
  • Please wear your Open Water Swimathon swim cap, which will be sent to you by post in September.
  • Submit your final time within your Swimmer Login at openwaterswimathon.org
  • SimplySwim is NOT part of an organised Open Water Swimathon session. You can complete your SimplySwim challenge in any venue of your choice, at your most convenient time.