Beppu Hyotan Onsen
- Location
- Beppu Oita Kyushu, Japan
- Water type
- sodium chloride
- Temperature
- 55 °C
- pH
- 3.5
Water profile
Relaxing — deep, immediate muscle release.
Loaded with major ions — the essential minerals (Ca, Mg).
Dense, salty water — you float without effort.
Beppu Hyotan Onsen sits within Beppu city on the northeastern coast of Kyushu, Japan's southernmost main island and home to arguably the densest concentration of hot spring activity in the world. Beppu's Oita Prefecture produces a staggering volume of geothermal water, and Hyotan Onsen is among its most celebrated neighbourhood bath houses — a multi-pool facility that has earned an international reputation without losing its fundamentally local, communal character.
The water here is notably hot at the source — 55 °C — and is cooled to bathing temperature across a variety of indoor and outdoor pools. Its sodium-chloride composition lends a pleasant mineral density to each soak, while a sharp pH of 3.5 signals a distinctly acidic spring, characteristic of the volcanic geology that drives Beppu's extraordinary thermal output. This acidity gives the water a clean, almost astringent quality on the skin that regular onsen visitors associate with the finest volcanic baths of Kyushu.