Fête du glaçon libre

A plunge into the frigid waters of Longueil-Sainte-Marie strips open water swimming down to its rawest essentials: bare skin, winter temperatures, and distances reaching up to a full kilometer. The Fête du glaçon libre is a winter open water swimming event held on a calm lake at the base de loisirs de Longueil-Sainte-Marie, in the Hauts-de-France region of northern France. Stepping onto the lakeside in the heart of winter presents an invigorating test against the chill, yet the gathering remains thoroughly inviting. While swimming in near-freezing water can sound intimidating, the format is deliberately structured to welcome every level of swimmer into the fold. Founded in 2025 by the local association Ois'eau libre, this cold and icy water competition was created as an open celebration of unassisted winter swimming.

Participants swim purely in traditional swimsuits without thermal neoprene suits, feeling the bite of the winter lake against bare skin. Rather than restricting the course to seasoned ice swimmers, the program offers lengths designed for everyone: accessible dashes of 50 and 100 meters, stepping up through 250, 500, and 750 meters, all the way to a challenging 1,000-meter test of endurance for veteran cold-water racers. Stepping into the water requires steady nerves, but the progression of distances lets each swimmer test their personal boundary in safety. Scheduled around Valentine's Day in mid-February, the event brings a festive, warmhearted atmosphere to what is otherwise one of the frostiest weekends of the year.

The Oise river and Île de Longueil-Sainte-Marie

The lake at Longueil-Sainte-Marie sits right in the fertile river basin of the Oise, close to the point where it joins with the waters of the Aisne. The Oise river divides around the Île de Longueil-Sainte-Marie, a slender ribbon of land stretching approximately 480 meters in length and just 50 meters wide. This narrow island splits the river's channel and serves as a vital hydrological pivot for the surrounding landscape. Civil engineering has long controlled the river current around this section of the Oise. The island is anchored to the left riverbank by a pair of navigation locks, while the right bank is regulated by the Verberie dam, completed between 2007 and 2009 to stabilize water levels and manage commercial river transit.

The Oise embraces other significant river isles, including Île des Meules. Measuring roughly 710 meters long and 300 meters wide, this larger island is harnessed between two banks by a dam on the left and the Sarron lock with its crossing bridge on the right.

River sand transport along the banks of the Oise

About four kilometres from the race grounds, at Villeneuve-sur-Verberie, an old 6.5-kilometre narrow-gauge tramway was built specifically to link inland sand quarries directly to the Oise river. The pit at Villeneuve operated at a brisk pace, producing 420 tonnes of extracted sand each day, an amount engineered to fill the cargo bays of one and a half river barges stationed at the water's edge. A similar sand-hauling network once crisscrossed the riverfront about nine kilometres away at Pont-Sainte-Maxence. There, a dedicated metre-gauge light railway transported heavy materials from the quarries of Fleurines and Villers-Saint-Frambourg directly to an active shipping wharf built along the riverbank. At the close of the nineteenth century, the Île des Rats was artificially excavated and sculpted in the Oise to streamline river transport.

Measuring about 790 meters long and 66 meters across, the island was equipped with a large lock chamber measuring 125 meters by 12 meters, designed to handle entire convoys consisting of a tugboat pulling five loaded barges at once. For decades, river barge crews tied up their vessels at the island to stock up on provisions at the local cafes and grocery stores, turning this working river channel into a lively hub for travelers of the inland waterways.

Forest of Compiègne and Saint-Sauveur springs

Rising across the river basin about thirteen kilometres from the race site lies the vast Forest of Compiègne, a historic expanse of woodlands that has maintained continuous tree cover since the final centuries of the Roman Empire. This rolling woodland landscape is deeply sculpted by water, characterized by open plateaus, steep gorges, undulating hills, and secluded ponds, all continuously drained and fed by the Oise and Aisne rivers along with dozens of small tributaries. Swimmers exploring the region after their icy plunge will find miles of quiet, damp forest trails winding along historic waterways. Human footsteps have traversed these humid woods since antiquity. Hidden within the Compiègne timberland lies a unique hydrological wonder known as the Spring of Saint-Sauveur.

This site features a pair of historic mineral springs celebrated for their therapeutic properties: one bubbling forth hot mineral water, while the second flows completely cold. For winter swimmers who have just emerged from the chilled lake of Longueil-Sainte-Marie, this dual thermal emergence in the nearby woods mirrors the ancient, restorative dialogue between extreme cold and soothing natural water.

Base de loisirs de Longueil-Sainte-Marie by the water

The immediate setting of the Fête du glaçon libre is the base de loisirs de Longueil-Sainte-Marie, a family-friendly, human-scale outdoor park built around a peaceful lake. The water's edge is edged by an artificial beach made of soft white sand, providing a clear and gentle entry point for swimmers wading into the chilly winter water. Goggles adjusted and toes in the sand, participants step off the quiet shore directly into the calm expanse of the lake, where no currents or ocean waves disturb the stillness of the winter air. While the winter event transforms the lake into an arena of icy resilience, the beach takes on a very different character during the warmer months.

In summer, the shoreline comes alive with families lounging on the sand and swimmers training in designated bathing areas watched over by lifeguards. The lake then fills with casual boaters taking out pedal boats, kayaks, and stand-up paddleboards across the open water, showing the versatile year-round life of this sheltered recreation basin. For winter competitors and their supporters standing along the shore, the base de loisirs provides essential comforts right beside the sand. Taking on the icy waters of the Fête du glaçon libre offers a rare, stripped-down test of grit, wrapped in the genuine friendliness of a lakeside community ready to warm you up the second you touch the shore.