Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesSodiumCalcium
This is a dynamic list of geothermal hot springs (onsen) as geological phenomena in Japan. This list is not for listing commercial establishments such as spa hotels, onsen ryokan, wellness centers or other commercial establishments.
Insider tip — Minami Yugawara is a secluded inner valley continuation of the famous Yugawara hot spring resort, its bicarbonate waters running along the forested Obaradani gorge. The handful of traditional ryokan here offer a quieter alternative to the busier main town, with baths positioned beside the rushing Kida River. Waters at 40°C have a smooth, slightly alkaline quality that soothes fatigued muscles after mountain hiking. The area is only an hour from Tokyo, making it an accessible single-night escape into deep nature.