Mashu Onsen
- Location
- Teshikaga, Hokkaido, 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.
Mashu Onsen, also known as Teshikaga Onsen, is situated in Teshikaga Town in eastern Hokkaido, serving as the thermal bathing hub for a region defined by the mysterious Lake Mashu — one of Japan's clearest lakes, perpetually veiled in mist and officially measured as among the most transparent bodies of fresh water in the world — located approximately ten kilometers from the spring itself. The iodine-rich thermal waters of Mashu Onsen are complemented by free foot bath facilities at Mashu Station and at the local road station, making geothermal bathing accessible to visitors of all means while the spring's two public baths serve the broader community of residents and tourists. Mashu Onsen invites visitors to rest and warm themselves in naturally iodine-bearing thermal water after exploring the extraordinary volcanic caldera landscape of eastern Hokkaido, where Lake Mashu, Lake Akan, and the hot spring districts of Teshikaga collectively form one of Japan's most spectacular wilderness thermal destinations.