62e Traversée Internationale du Lac St-Jean 32km

In late July, the town of Roberval undergoes a profound transformation as it prepares for the annual 32km marathon swim across Lac St-Jean. For weeks, the atmosphere builds through local traditions, such as the massive street dinner that draws thousands to long, communal tables. By race morning, the focus shifts entirely to the water, where the legacy of this crossing—a cornerstone of professional open water swimming since 1955—becomes tangible. This event, which notably hosted the 2010 FINA World Open Water Swimming Championships, remains a singular test of endurance in a basin with deep, ancient origins.

The character of the water

As swimmers push off from Péribonka toward the finish line at Roberval, they navigate a landscape shaped by the retreat of the Laurentide Ice Sheet; the basin itself was once submerged under the Laflamme Sea, which left behind thick layers of fluvial sediments that define the lake floor today. Known to the local Pekuakamiulnuatsh First Nation as Piekuakamu, these waters are more than a racing venue; they are a site of deep cultural history. Swimmers often find their perspective shifted when passing the Pointe-Bleue headland, a prominent geographic marker on the western shore that serves as the heart of the Mashteuiatsh reserve. The name, rooted in the local Innu language, translates simply to 'where there is a point,' a reminder of the long-standing presence of the Indigenous people in this region. While the marathon provides a singular challenge for the professionals, those seeking a shorter distance can explore these same vast, open waters during the 1-2-5km Uniprix Julie Beaupré event, held just one day prior. The scale of the lake, with its 1,053 km² surface area, demands respect for the changing conditions that can emerge throughout the 32km journey. Past racers often cite the mental fortitude required to navigate the vast, relatively shallow expanse, a testament to the endurance legacy established by pioneers like Jacques Amyot during the inaugural 1955 crossing.