Tamagawa Onsen, Semboku, Akita Prefecture
Tamagawa Onsen Day Bath
A spring-to-autumn destination for the Great Boiling Spring, natural rock-bed bathing area and long-standing therapeutic-bathing culture. The main building closes in winter; switch to Shin-Tamagawa Onsen then.
Check before bathing
- Opening hours
- Day use: 10:00–15:00, last admission 14:30. Adult admission is ¥1,000 and child admission ¥500. The main Tamagawa Onsen building closes in winter; indoor rock-bed bathing is for overnight guests only.
- Access
- The usual approach is by bus from Tazawako Station. In winter, National Route 341 is subject to seasonal restrictions; check road and bus service before travelling.
Spring & water temperature
- Spring-source temperature
- 98°C at the Great Boiling Spring; this is not bath temperature.
- Bathing temperature
- Not published; the hotel adjusts even the 100% source pool to bathing temperature.
- Spring source
- Obuki (Great Boiling Spring), shared with Shin-Tamagawa Onsen.
- Spring classification
- Strongly acidic spring whose main component is hydrochloric acid, as described by the hotel.
- pH
- 1.2.
- Flow rate
- About 9,000 L/min at the Great Boiling Spring.
- Water handling
- The large bath has pools using 100%, 50% and weaker spring concentrations. Not every pool uses undiluted source water. Pool-by-pool addition, heating, circulation and disinfection details are not fully published.
Bathing indications
The hotel's bathing and therapeutic-stay information is general spring-use guidance, not a guarantee of medical benefit. The highly acidic water calls for shorter, careful soaks.
Winter closure applies to the main Tamagawa Onsen building. Admission is limited to 10:00–15:00, with last entry at 14:30. Tattoos policy is not confirmed.
How to read a bath profile
Spring-source temperature and actual bathing temperature are kept separate. Each score is shown independently for comparison rather than collapsed into one overall score.
