Asahidake Onsen Pira no Yu

This is a wild bath, not a built facility: a set of natural rock pools with no roof, attendant, or amenities. It sits about 15 to 30 minutes on foot from the base of the Asahidake ropeway, through brush and wetland at the foot of Mt. Asahidake in Daisetsuzan National Park. There is no washing area, no towel rental, and no formal water analysis, just spring water pooling naturally among the rocks. Asahidake Onsen itself is one of Hokkaido's older hot spring areas, but this particular pool is unmanaged and unmarked, so come prepared for rough terrain and bring everything you need.