Nagasaki · Unzen Onsen
Unzen Kojigoku Onsen-kan
雲仙 小地獄温泉館
A historic cure-bath in the hills a short way from Unzen's main street, said to have hosted Siebold and Yoshida Shōin. An octagonal wooden bathhouse with milky sulfur water cooled from a 90°C source. No open-air bath, but Unzen's finest water.
- Price (adult)
- ¥500
- Hours
- 09:30–19:00 (until 20:00 in summer)
- Closed
- Wednesdays (open if a holiday)
- Access
- 20 min walk or 5 min drive from Unzen Onsen bus stop
- Water type
- Sulfur spring
- Tattoos
- Ask ahead
- Admission
- Adults ¥500 / elementary and under ¥250 / under 3 free. Cash only (ticket machine). JAF discount. Seiunso guests get half-price tickets at reception. On the Kyushu 88 Onsen list. Soap, shampoo, dryers and lockers free; towels ¥200
- Baths
- Opened as a cure spa in 1731 and reputedly visited by Yoshida Shoin. A communal bath since 1919; the present wooden building dates from 1993 — its walls blackened by the spring’s minerals. Hot and mild indoor tubs per gender (90 °C source cooled with spring water), a large tatami lounge and a shop. No rotenburo
- Water
- Simple sulfur spring (hydrogen-sulfide type), mildly acidic pH 4.3, 90 °C at source. Right below the source, so the milky water is fresh and richly sulfurous — Unzen’s biggest flow. For neuralgia, poor circulation, frozen shoulder, fatigue
- Parking
- Free, 200 cars (shared with Seiunso). 5 min by car or 25 min uphill on foot from Unzen village
- Phone
- 0957-73-3273
- Official site
- seiunso.jp ↗
- Open in Google Maps
- Google Maps ↗
Essentials
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Why go
- Octagonal wooden bathhouse
- Free-flowing milky sulfur water
- Part of the Kyushu 88 Onsen trail
A blackened timber bathhouse over the source itself
Kojigoku (“little hell”) Onsenkan is a communal bath in the fumarole field about 1.5 km up a forest road from Unzen village, begun as a cure spa in 1731 and reputedly visited by the scholar Yoshida Shoin. The wooden building of 1993 has walls turned jet black by sulfur, striking among the trees. The 90 °C source rises right behind the building and is cooled only with spring water, so the milky bath is always fresh; hot and mild tubs let you linger. For ¥500 you get soap, shampoo and lockers, plus a large tatami lounge to sprawl in — widely rated Unzen’s best value.
Tips & cautions
- Closed Wednesdays (open on holidays). Until 19:00 in winter (Nov–Apr), 20:00 in summer. Cash only.
- No rotenburo, just two tubs — it’s about fresh water, not size.
- Strong sulfur smell lingers on clothes; remove jewellery.
- 25 min uphill from the village; walk up and catch the bus down from Seiunso.
- Combine with the free trail through the Kojigoku fumaroles behind.
- Least crowded right after the 9:30 opening.
Getting there
5 min on foot from the “Kojigoku-iriguchi” bus stop at Seiunso (Obama-cho Unzen 500-1). 5 min by car or ~25 min on foot from Unzen village; ~1 h 25 min by bus from Isahaya Station. Free parking for 200.
Before you go
- No official tattoo policy is published — ask at reception.
- The water runs hot (43–45°C). Don't add cold water; take short repeated dips instead.
- Payment is usually by ticket machine in cash — bring coins.
- Last entry is 30–60 minutes before closing.
Features
Price
Mood & scenery
Amenities
✔ Verified operating: 2026-09 Operating status and rates cross-checked against the official site and onsen guides (full source notes in Japanese on the JA page)
Prices and hours change. Check official sources before visiting.
More in this area
Unzen Yokayu
A day-bath with a simple lodging near the entrance to Unzen Jigoku. Every tub is free-flowing milky sulfur water — indoor, open-air and four private outdoor baths. ¥500, 9 am to 9 pm; an easy stop before or after touring the 'hells'.
Obama Onsen Wakihama Public Bath (Otasshan-yu)
A communal bath in Obama Onsen on Tachibana Bay, whose ~100°C springs release more heat than any in Japan. The single-storey wooden building from 1937 feels like a museum of Showa-era life and is a designated prefectural townscape asset. Pay at the old-style counter, then choose between the hot and very hot tubs of free-flowing chloride water. Open from 6 am; part of the Kyushu 88 Onsen trail. About an hour from Nagasaki city, on the way back from Unzen.
Shimabara Onsen Yutorogi-no-yu
A municipal day-use onsen entered straight from the Shimabara Ichibangai shopping arcade in this spring-water castle town. Magnesium-sodium bicarbonate water (source 61.8 °C) is used free-flowing — clear, colourless and soft on the skin. The building has a retro Shōwa-era bathhouse feel, with a sauna and tatami rest hall; admission ¥530, or ¥320 for over-70s. Open 10:00–21:00 (last entry 20:30), closed Wednesdays. Within walking distance of Shimabara Castle, the samurai quarter and the carp-stream streets, and a handy stop between Shimabara port and Unzen. Parking free for two hours.
