The Ultra Trail de l'Île d'Oléron begins and concludes at the Citadel of Le Château-d'Oléron, situated on the largest island within the Charente archipelago, off France's Atlantic coast. The primary event is a 100 km trail loop encircling the island, typically held in early April.
With minimal elevation gain of approximately 500 meters, the difficulty stems from the distance, terrain, climate, and exposure rather than significant ascents. Participants may complete the entire loop individually, with a partner, or as part of a four-person relay team. The event also features a 12 km walk, alongside races for children and juniors.