Yui Onsen

Yui Onsen rises at the confluence of the Shimanto River—Japan's last undammed major river, celebrated as one of the country's most pristine waterways—and the Hiromigawa River in Shimanto City, Kochi Prefecture, where simple thermal waters emerge within a landscape of extraordinary river ecology and natural beauty in the deep mountain interior of Shikoku island. Surrounded by forested mountains where camping, canoeing, and cycling are the primary pleasures of visitors drawn to the Shimanto's wild, clear waters, the spring provides the perfect post-activity recovery—warm mineral immersion after a day on the river or along the riverside trails. The combination of Japan's most celebrated wild river, outdoor recreation, and a simple thermal spring creates a Kochi destination of exceptional natural and restorative character.