Unzen, Nagasaki Prefecture
Unzen Seiunso
A hotel day bath with source-flowing sulfur water in its indoor, outdoor and private baths. Public bathing is available in a clear daytime window; school-trip groups can temporarily suspend access on specified dates.
Facility photos
Check before bathing
- Opening hours
- Public baths and private baths 11:00–18:00; last admission 17:00. No regular closing day was listed in the facility's 2026-07-30 confirmation. Public admission: adults ¥880, children ¥440 and under-threes free. A private bath costs ¥2,500 per room for 50 minutes, in addition to admission; two adults come to about ¥4,260 total. School-trip bathing can temporarily close both public and private areas on specified dates.
- Access
- Near Kojigoku Iriguchi; buses serve Nagasaki, Isahaya and Shimabara. The hotel lists up to 200 parking spaces and may offer a free pickup around the Unzen hot-spring district; confirm the service before relying on it.
- Tattoo policy
- The current day-use and FAQ pages reviewed do not confirm a tattoo rule. Booking a private bath does not guarantee tattoo access; ask the hotel first.
Spring & water temperature
- Spring-source temperature
- 51.1°C in the current spring analysis; older promotional copy gives 65–70°C, so the newer analysis is used.
- Bathing temperature
- No fixed pool temperatures are published. Older supply notes give about 40–43°C after natural cooling in the pipes, with spring water sometimes used at the bath to cool further; these are not fixed readings for every pool.
- Spring source
- Unzen Onsen, Kojigoku source area.
- Spring classification
- Simple sulfur spring, hydrogen-sulfide type; low-salinity, weakly acidic and hot spring.
- pH
- 4.41 on site and 4.90 in the 2026 laboratory analysis; facility copy still rounds this to pH 4.3.
- Flow rate
- A per-minute yield is not published. The operator's broader supply description gives about 440 tonnes per day; it is not converted here to L/min.
- Water handling
- The operator says the indoor, outdoor and private baths are all source-flowing and drained after use. If the source is too hot, local spring water may be used to cool it before it reaches the bath; the hotel says tap water is not used.
- Analysis date
- 2026
A weakly acidic sulfur spring can irritate sensitive skin or mucous membranes. Seek medical advice if you have a chronic condition or feel unwell.
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.
