Ooka Onsen
Ooka, Nagano, Japan
- Location
- Ooka, Nagano, Japan
- Water type
- bicarbonate
- Temperature
- 40 °C
- pH
- 8
Water profile
Thermicity
Sedative
LowHigh
Relaxing — deep, immediate muscle release.
Mineralisation
Restorative
LowHigh
Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesSodiumCalcium
Ooka Onsen, in the village of Ooka (Nagano), circulates bicarbonate water with a pH of 8, at 40°C, between an indoor bath and an open-air outdoor bath, with a sauna.
Insider tip — Ooka Onsen serves the small agricultural community of former Ooka-mura, now part of Nagano city, perched on a plateau between the Chikuma River valley and the western ranges. The rural quiet and the bicarbonate spring water together provide a restorative experience far removed from the urban pace of Nagano city below.
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 bicarbonate water.
What is the best season to visit?
The most favourable period for this spot is: Toute l'année.