法華院温泉山荘ほっけいんおんせんさんそう
Kyushu's highest onsen, a hike-in mountain hut in the Kuju range
Uses natural hot spring water
Open-air outdoor bath
Enclosed indoor bathing area
Sauna room of any kind
A private bath you can reserve for yourself or your group
Private onsen bath in guest rooms, for overnight guests only
Shared bathing area for all genders
Welcomes children and families
Room-rate table lists a discounted 小学生以下 (elementary-school-and-under) rate alongside the general rate, implying children are accepted; no explicit age-restriction policy stated.
A restaurant or dining room open to visitors, not only meals for overnight guests
Shower, wash stations, soap and shampoo provided
Confirmed independently by a 2025 Japanese review: '温泉がありますが、石鹸等は使えないので浸かるだけです' — no shampoo/soap use permitted, to protect the water source in the national park.
Towels to rent or borrow at the desk
Towels are sold at the shop, not rented; multiple reviews also say to bring your own towel.
On-site or nearby parking available
MountainsThe bath at Hokkein Onsen Sansou sits in the Bogatsuru basin, deep in the Kuju mountains at around 1,303 meters, the highest hot spring in Kyushu. It's a single indoor tub with big windows facing the peaks of Taisen, Hiji, and Tacchu, plus an open deck outside for cooling off and looking at the stars after dark. The water isn't diluted or recirculated, just warmed in the colder months, and soap or shampoo aren't allowed since it drains straight back into the mountain. There's no road in. Every route here, from Makinoto Pass or from Chojabaru, is a two- to three-hour hike, and the lodge doubles as a rest stop for hikers crossing the Kuju range. It opened as a mountain hut in 1882, on ground that had been a Buddhist retreat since the Kamakura period, and it still runs the old way: phone reservations only, cash only.
Loading map…
5.0
1 review
I was there quite a while ago, so I’m writing from memory since this onsen is unique. It’s located among the mountains, accessible on foot, a couple of hours’ walk, with a great free campsite nearby. The onsen is pleasant, with a small view, everything was modest and clean, but the main thing is the chance to soak in a hot bath and wash up after hikes in the surrounding mountains. There is food and a drink vending machine.
Last updated October 7, 2026