UltraSwim 33.3 Switzerland 2026 — Lac Léman

The current tugs gently at your stroke as you pass the Île Rousseau, a small, tree-lined sanctuary mid-river where a bronze statue of the philosopher marks the transition between the lake and the Rhône. Below you, the depth shifts rapidly; you are swimming where the massive volume of Lake Geneva funnels into the city’s heart. To your right, the 15th-century walls of the Temple de Saint-Gervais rise near the bank, a site built upon ancient burial grounds that hold stories of medieval Geneva. You navigate past the Pont de la Machine, a 19th-century structure that once powered the city’s water pumps, feeling the slight acceleration of the water as it pushes toward the city center.

A multi-day lake challenge

This is the UltraSwim 33.3 Switzerland, a four-day series that demands both endurance and precision across a total of 33.3 kilometers. Unlike the coastal swells of Course autour du Phare, this fresh water environment remains largely protected, though the afternoon thermal breezes can challenge your rhythm. The event structure is built to develop your capacity: you start with shorter, manageable distances, building up to a marathon-length swim on the third day. Participation costs 1500 CHF, a fee that covers the extensive logistics required for a multi-day lake traversal, including support vessels and maritime safety coordination for the country-to-country crossing between Switzerland and France.

Race day logistics

While the water is fresh and lacks the buoyancy of the sea, its clarity allows you to track your line with ease. Wetsuits are permitted throughout the event, providing extra warmth for the longer daily efforts. If you are preparing for a long-distance crossing, you might find this format more structured than the point-to-point nature of La Traversée. The local currents are subtle but persistent, particularly near the outflow areas, requiring constant attention to your navigation. As you finish your final session, you will pass beneath the Pont de la Coulouvrenière, marking the conclusion of your four-day journey through the historic waterways of Geneva.