Yunokuchi Onsen (Yumoto Sansō)
A hidden spring on the site of an old copper mine in the hills of Kumano, Mie. The abundant water is entirely free-flowing with no dilution or heating; the clear sodium-chloride spring warms you to the core. The cedar-scented bathhouse, rebuilt in 2015, has an indoor bath, an open-air area with standing, half-body and lying baths, and a private bath for ¥1,080 per hour. Admission ¥600 for adults, open 09:00–21:00 (last entry 20:15), irregular closures. A trolley train through the old mine tunnel (about 10 minutes) links it with Iruka Onsen Seiryūsō and is a famous ride in itself — but as of 2026 it is suspended for safety inspections, so check ahead. Half-price admission on the 26th of each month. About 40 minutes by car from Kumano-Ōdomari IC.
