2023 UltraMarathon Swim Series

The World's Coldest, Hardest, Longest, Toughest, Most Extreme Swims By, for and about ultramarathon and extreme swimmers

July: 36 km Maratona del Golfo Capri-Napoli in Italy – June 23 – June 27- July 7 – Elite Race September 9, 2023

July: 14.5 km Authentic Marathon Swim in Greece – July 2023 (Pending date first week of July 2023)

July: Trans Tahoe in the USA – July 15, 2023

July: 32 km Traversée internationale du lac St-Jean (32 km) in Canada – July 22 – 29, 2023.

September: Travessia Lisboa – Cascais in Portugal 20km– September 23, 2023

September: DC Marathon Swim in the USA – June 20, 2023, October 1, 2023, October 15 2023

October: 20k and 30k La Isla Open Water in Mexico-  October (Pending dates 2023)

Please view the WOWSA Rules and Regulations and 2023 UltraMarathon Extreme Swim Series rules

The Travessia Lisboa Cascais 20km Open water swimming race is a point-to-point race starting at Belém Dock in Lisbon and finishing at Pescadores Beach in Cascais, Portugal. The race includes approximately 9km in the river and 11km in the ocean, with the tide flow speeds inside the river normally greater than 1.5 m/s (5.4 km/h) and can reach 2.5 m/s (9 km/h) in the Tejo estuary and along the stunning coastline.

Race September 23, 2023

Maratona del Golfo Capri-Napoli is one of the longest running professional marathon swimming competitions in the world which began in 1954 and starts on the island of Capri and finishes 36 km (22 miles) later on Marina Grande Beach in Napoli on the mainland of Italy. Learn more

Elite Race September 9, 2023

Each summer since 1955, the Traversée Internationale du lac St-Jean attracts the world’s elite professional open water swimmers to Roberval. One of the world’s most prestigious professional races with a long and rich history.Water temperature and winds can vary, but water temperature under 20°C (68°F) is expected. Learn More

July 22 – 29, 2023

The Trans Tahoe Relay started in 1976 and has become an annual reunion of the global open water swimming community. Traditionally done as a relay, WOWSA has partnered with the Olympic Club to offer Trans Tahoe Solo (15.5k) as part of the Ultramarathon Swim Series.
July 15, 2023

La Isla Open Water is the only one 20k and 30k competition in Presa Zimapán, Cadereyta de Montes, Querétaro, Mexico held at the end of October. It is one of the Mexico’s Top 50 Open Water Swims. The races attracts about 30 swimmers in the 20k and 30k distances and 300 swimmers in the other distances.

October 2023

The Authentic Marathon Swim represents the revival of the authentic marathon swimming route, 2.500 years after it was first accomplished. The event includes 14.5km route at the straits of Artemision – the location of the historical Naval Battle between Greek and Persian forces in Greece.

July 2023 (Pending day)

The DC Marathon Swim is a 20.5 mile epic adventure from Chain Bridge to Mount Vernon. Navigating your way through Washington DC in the Potomac River, tides, currents, changing winds will challenge your open water skills and endurance. The event takes place in the United States.

June 20, 2023, October 1, 2023, October 15 2023