Akaigawa Caldera Onsen; Hoyo Center
Akaigawa, Hokkaido, Japan
Illustration photo — not a verified picture of this exact spot.
- Location
- Akaigawa, Hokkaido, Japan
- Water type
- iron-rich
- Temperature
- 40 °C
- pH
- 6.3
Water profile
Thermicity
Sedative
LowHigh
Relaxing — deep, immediate muscle release.
Mineralisation
Bio-active
LowHigh
Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
FerBicarbonatesManganèse
The Hoyo Center at Akaigawa Caldera Onsen, on Hokkaido, taps mildly acidic (pH 6.3) iron-rich water rising from an old caldera at 40°C, with an indoor bath, an outdoor rotenburo and a sauna.
Insider tip — The Akaigawa Caldera Onsen Hoyo Center sits inside the ancient Niseko-Shakotan-Otaru Quasi-National Park caldera in central Hokkaido, surrounded by cedar forest and river valleys. The iron-rich waters emerge from the caldera floor at 40 degrees Celsius and carry a distinctive reddish-brown mineral tinge. The facility is popular with Hokkaido families for weekend getaways and relaxing baths. In late autumn the caldera walls turn vivid red and gold, making the outdoor baths especially memorable.
Nearby
Frequently asked questions
How hot is the water?
The water runs quite hot here, around 40 °C — a sedative water that brings immediate muscle release.
What type of water is found here?
This spot features iron-rich water.
What is the best season to visit?
The most favourable period for this spot is: Toute l'année (idéal automne-hiver).