Tsukui Onsen
- Location
- Tsukui, Sagamihara, Kanagawa, Japan
- Water type
- sodium chloride
- Temperature
- 41 °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.
Tsukui Onsen draws visitors to a valley dominated by Lake Tsukui, a major reservoir created by the Tsukui Dam on the Sagami River that supplies drinking water to the densely populated cities of Yokohama and Kawasaki — making this seemingly rural body of water one of the most strategically important reservoirs in all of Japan. The surrounding gorge and forested hillsides of the Tsukui valley offer excellent hiking trails that traverse secondary forests rich with wildflowers in spring and brilliant foliage in autumn, providing a natural escape within easy reach of greater Tokyo. The onsen's geothermal mineral waters, rising from the depths of the Tanzawa geological zone, offer warm restoration to hikers and day-trippers exploring this important and beautiful watershed.