Leiden Swim viersdaagse & Cannonball Championship

The four day swimming event always takes place in the last “full” week of August. In 2025, enthusiasts can take part in the 49th swimming four-day event from Monday 25 to Friday 29 August. The event will take place at Zwembad De Vliet on Voorschoterweg 6, in Leiden.

During the Leidse Zwemvierdaagse, you can start from 19.00 to 20.15 in the outdoor pool of Zwembad De Vliet with a valid participation ticket.

Supporters are welcome to come and cheer on the participants. The restaurant in De Vliet will be open during the four-day swimming event.

After four evenings of swimming laps, the Leiden Zwemvierdaagse will end on a festive note on Friday evening, August 29, 2025, with a splashy new event: the 1st edition of the Leiden Cannonball Championship!

Anyone with a swimming diploma – young or old – is welcome to join, preferably in a bold and flamboyant swim outfit! From classic cannonballs to creative jumps: anything goes. Wow the audience with your most beautiful, wacky, or spectacular cannonball. The more original, the better! A panel of expert judges will score the jumps based on height, splash factor, and originality. The winner will take home a unique trophy – and of course, eternal glory!

There’s room for 50 participants, so sign up quickly. Entry costs €2.50 in advance or €5.00 at the door (if spots are still available).

The championship will start around 8:45 PM and end around 10:00 PM.