River Shimanto Ultra Marathon

The River Shimanto Ultra Marathon is widely regarded as one of Japan’s premier ultramarathons and offers runners a rare opportunity to experience the pristine beauty of the Shimanto River, often called Japan’s last clear stream. Held each autumn in Kochi Prefecture on the island of Shikoku, the race combines a challenging ultra-distance course with spectacular scenery, warm local hospitality, and a deep commitment to environmental conservation. Rather than focusing solely on competition, the event celebrates the connection between runners, volunteers, and the communities that line the river, creating an atmosphere that many participants describe as uniquely welcoming and memorable.

Participants can choose between a 100 km race and a 60 km race, both following the winding Shimanto River through peaceful mountain valleys, forests, traditional villages, and the region’s famous chinkabashi (submersible bridges), which are designed to flood safely during periods of high water. Along the course, runners are treated to stunning views of crystal-clear rivers, lush countryside, and local landmarks that showcase rural Japan at its finest. Numerous aid stations provide generous refreshments, regional specialties, and enthusiastic volunteer support, helping competitors tackle the demanding distances while enjoying the area’s renowned hospitality.