Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
SoufreSulfuresSulfates
Jinata Onsen sits on Shikinejima island off Tokyo, where turquoise-tinted sulfurous water emerges close to the shoreline. An indoor bath and an ocean-facing outdoor bath (rotenburo), plus a sauna, make for a striking escape from the capital.
Insider tip — Jinata Onsen is an iconic onsen on Shikinejima Island (Izu Islands, Tokyo), freely accessible in a natural cave by the sea. A sulfurous, highly acidic geothermal spring (pH 1.8!) formed in a rocky crevice overrun with colourful algae — one of Japan's wildest and most photogenic onsen. Shikinejima is a 3-hour boat ride from Takeshiba, Tokyo.