Shikishima Onsen; Utopia Akagi
Shibukawa, Gunma, Japan
- Location
- Shibukawa, Gunma, Japan
- Water type
- sodium chloride
- Temperature
- 41 °C
- pH
- 7.3
Water profile
Thermicity
Sedative
LowHigh
Relaxing — deep, immediate muscle release.
Mineralisation
Restorative
LowHigh
Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Effortless float
LowHigh
Dense, salty water — you float without effort.
SodiumChloruresBrome
Utopia Akagi, in Shibukawa, Gunma Prefecture, draws on sodium-chloride water at 41°C. The facility combines an indoor bath, an open-air rotenburo and a sauna.
Insider tip — Utopia Akagi at Shikishima Onsen serves the Akagi foothills of Shibukawa City where the dormant Akagi volcanic massif rises from the Gunma plain. Shibukawa proudly marks the geographic center of the Japanese archipelago and sits at the crossroads of hot spring routes connecting the Ikaho, Shima, and Kusatsu spa resorts — making the Gunma mountain zone Japan most concentrated thermal tourism destination. The Akagi caldera lake (Onuma) above the city is one of Kanto most atmospheric volcanic crater landscapes.
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 sodium chloride water.
What is the best season to visit?
The most favourable period for this spot is: Toute l'année.