Shirarahama Musashi Onsen
- Location
- Shirahama, Wakayama, Japan
- Water type
- sodium chloride
- Temperature
- 39 °C
- pH
- 7.3
Water profile
Relaxing — deep, immediate muscle release.
Loaded with major ions — the essential minerals (Ca, Mg).
Dense, salty water — you float without effort.
Shirarahama Musashi Onsen is one of the Shirahama resort area's coastal hot springs in Wakayama prefecture, where chloride-rich sodium waters from the Shirahama geothermal system flow in one of Japan's oldest documented thermal resorts — recorded in the Nihon Shoki chronicle in 658 AD when Emperor Saimei visited within a long imperial thermal tradition. Shirahama's iconic Saki-no-yu cave bath, where geothermal water and Pacific Ocean waves meet in a natural coastal grotto, represents the quintessential Japanese coastal onsen experience of thermal immersion at the literal edge of the ocean. The white sand of Shirahama beach — artificially supplemented with sand imported from Australia to replace erosion losses — and the dramatic Hashiguiiwa basalt rock formations bookend an oceanside thermal resort of exceptional historical depth and scenic beauty.