The UltraSwim33.3 Season 2025

Our 2025

Imagine gliding through turquoise waters off the coast of Skopelos, sunlight flickering beneath you as dolphins swim nearby. UltraSwim33.3 in Greece takes place in the wild island landscapes of white cliffs and green pines, meeting water so clear you can see the ripples of sand on the sea floor. This year, we had hot sunny weather with strong winds coming around the North tip of the island. We had to change the course a few times so the swimmers weren’t up against the waves. Adaptability is a key part of adventure, open water swimming! The morning air buzzed with excitement as swimmers gathered together on the beach, their chatter and nervous laughter mixed with the hum of boats as they prepared for their epic adventure swim. Each morning, the air felt charged with anticipation with the swimmers preparing for the ultimate test of endurance. Aboard the transfer boats, there were stretching groups on the top deck and dance parties down below while the captain played ABBA all the way! So, prepare for a Mamma Mia-themed adventure on the wild island of Skopelos, ditch the wetsuit and pack your flares!

Skopelos Island, #9Greece

Montenegro was where it all began for UltraSwim33.3. You will swim through the fjords of the black mountains and around and incredible amount of Balkan history. On the day of the marathon swim for our 2025 event, the swimmers started at the monastery which had been built upon its own island. The clouds sat on the top of the mountains and let a stream of sunlight through the church spire. The swimmers hugged the coastline as they swam past some incredible wonders of Montenegro. The first was a shipwreck from the Yugoslav War, a huge steel warship lying on its side on the water's surface. Then onto a submarine pen at about 8km, an abandoned Cold War military facility. What used to be disguised in the face of the mountain is now an open feature in the Bay of Kotor, open for the swimmers to swim into it. Talk about adventure swimming! We had a swimmer with us who worked for NATO and he swam all the way with a NATO flag in his tow float to get a photo inside the pen to show his colleagues. This swim gives the perfect taste for what Montenegro is and is the best way to experience a new country.

#10Montenegro

Set on the fresh waters of Lake Geneva (Lac Léman), bordered by the Swiss and French Alps, the Switzerland event features the iconic Lausanne–Evian crossing. The freshwater conditions shift buoyancy and work the tides in ways unlike the sea. The route crosses between nations during the stretch from Switzerland into France, offering not just physical demands but an expansive, alpine horizon as your backdrop. Even in the heart of the alps, water temperatures hover around 22-25 °C in the summer. We had the pioneer event in 2025, ready to be open to the public for 2026. The lake’s calm early mornings gave way to wind-swept afternoons, so open-water swimmers must expect variety but that’s the nature of an alpine swim. Here, your mental game matters just as much as your stroke: the long swims, fresh water feel, and changeable conditions make it a true test of resilience, showing what endurance open water swimming is all about.

Lac Léman #8Switzerland

In the coastal waters of Croatia, swimmers take on the 33.3 km challenge amid a breathtaking island-hopping adventure. This event is unique in that it is the only one where swimmers can take on the ultimate format, swimming either 22.2km or 33.3km in one go. This is taking long distance swimming to the next level, offering swimmers a chance to swim the English Channel distance in a stunning Mediterranean location. This year, we had one person finish the ultimate 33.3 distance, the first person to ever swim from Stari Grad to Hvar Town. The course winds through turquoise channels between rocky isles off Hvar, past historical stone forts and through deep-blue Adriatic basins. It’s a swim where the natural beauty of Croatia, with the sun-lit cliffs, crystalline water, and island life, mean you will never get bored of the setting. It’s the perfect balance of culture and serenity.

#7Croatia