Les 3 heures du Soubestre is a three-hour running race held at the Plaine des sports in Serres-Castet, organized by Les Coureurs du Soubestre. Rather than a set distance, participants aim to complete as many 5.1 km circuits as possible before time expires. Each circuit combines trail and road sections and features approximately 120 meters of elevation gain, making the race suitable for those seeking a challenge beyond a simple flat road loop. It is open to all participants and can be completed individually, as a two-person relay, or as a three-person relay.
Solo participants can utilize the format for extended training, while the relay choices offer a way to compete intensely or share the event with friends and colleagues. The repeating course design keeps runners near the event hub, where supporters can observe the race from a fan area equipped with a sound system, music, drinks, a refreshment stand, inflatable structures, and supervised activities for children. Fifty percent of the proceeds benefit Cody coeur de champion, an organization supporting families impacted by childhood cancers.