Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
FerBicarbonatesManganèse
Senzuru Onsen, in Tanabe, Wakayama, is a Japanese thermal bathhouse with iron-rich water. The water emerges at around 41°C. The bathhouse offers an indoor bath, an open-air bath (rotenburo) and a sauna. A simple spot, valued for its neighbourhood feel.
Insider tip — Senzuru Onsen is situated in the Tanabe district of Wakayama Prefecture, gateway to the Kumano Kodo pilgrimage routes and the Kii Peninsula's dense spiritual forests. The iron-rich waters emerge with a characteristic amber-brown hue and metallic scent, properties long associated with restorative benefits for the blood and joints. Pilgrims on the ancient Kumano trails have soaked in similar ferruginous springs along this coast for centuries. Pair a visit with a walk along the Nakahechi trail through cryptomeria forests to fully experience the Kii Peninsula's healing landscape.