Aso Onsen; Shiraho no Yu
Tsukuba, Ibaraki, Japan
Illustration photo — not a verified picture of this exact spot.
- Location
- Tsukuba, Ibaraki, Japan
- Water type
- iron-rich
- Temperature
- 41 °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
Aso Onsen (Shiraho no Yu) is located in Tsukuba, a university city in Ibaraki Prefecture. The iron-rich water flows at 41°C, pH 6.3. It offers an indoor bath, an outdoor rotenburo bath and a sauna.
Insider tip — Aso Onsen Shiraho no Yu serves the Tsukuba Science City area of Ibaraki with iron-rich spring water that offers a genuine contrast to the high-tech, research-oriented character of the surrounding district. The amber mineral bath is particularly popular with university staff and JAXA researchers seeking physical relaxation after long hours at their desks. The name 'shiraho', meaning white sail, evokes the sweeping flatness of the Kanto plain visible in every direction from the bath's upper-floor windows. The water's mild iron content is gentle enough for daily bathing, which many regulars practice throughout the year.
Nearby
Frequently asked questions
How hot is the water?
The water runs quite hot here, around 41 °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).