Osez Hostens - Natation en Eau Libre

Dr. Pirinski, a Bulgarian physician who once made this corner of the Gironde his home, commissioned a manor house that still stands as a curious architectural anomaly. With its dungeon, watchtower, and corbels, the building serves as a whimsical landmark for those arriving at the lakes of Hostens. While the doctor likely enjoyed the tranquility of the region, today's visitors find a landscape defined by a different kind of history: the deep, man-made basins of Lake Lamothe and Lake Bousquey. These waters were not carved by ancient glaciers, but by industrial hands extracting lignite—a dense, dark fossil fuel—between the 1930s and 1966. As you swim, you are effectively navigating an open-pit mine that has been reclaimed by the forest and filled with groundwater dating back to the Pliocene epoch, some five million years ago.

Navigating the Pliocene basins

The Osez Hostens event takes place within this former mining site, where the water is calm but requires a watchful eye on the horizon. The region’s temperate climate often brings sudden, localized summer storms, occurring on average 15 to 20 days per year; race organizers monitor these patterns closely to ensure safety during the events. For the swimmers, the experience is framed by the sight of the neo-Gothic Saint-Pierre church, whose tower has watched over the village since 1903. The race day itself offers distances of 500m, 1000m, and 1500m, with entry fees ranging from 10€ to 35€ depending on the format and registration timing. The event, managed by the local Gironde swimming federation, emphasizes accessibility, offering a relay format and the 'Osez un tour de +' challenge, where participants must complete successive loops within diminishing time windows. Whether you are circling the white sands of Lake Lamothe or passing by the ornithological sanctuary of Lake Bousquey, the course provides a rare opportunity to swim through a landscape shaped by millions of years of geology and a century of human industry.