Babadani Onsen

A proper wild onsen (野湯, yauyu) that takes some effort to reach, about 50 minutes on foot from Keyakidaira station deep in the Kurobe Gorge. The bath itself sits right on the riverbed: a sulfur spring where hot water seeps up through the gravel and mixes with the cold mountain river, so you find your own temperature by shifting around. Monkeys are regular visitors, the gorge scenery is spectacular, and in autumn the changing leaves make the walk in as memorable as the soak.