Adult ¥700 / Child ¥350; last entry 20:00; may be restricted on Saturdays, holidays, and for large groups after 15:00
Uses natural hot spring water
Open-air outdoor bath
Enclosed indoor bathing area
Dry heat sauna room
Cold water plunge bath, typically used after sauna
Private onsen bath in guest rooms, for overnight guests only
Shared bathing area for all genders
Restaurant or dining open to visitors (not just hotel meal plans)
Shower, wash stations, soap and shampoo provided
On-site or nearby parking available
A cold-mineral source (19.6 °C) heated for bathing, classified as a strongly alkaline simple thermal water. Lightly mineralized at just 0.326 g/kg dissolved solids, it is mild on the body, while the pH 9.5 strong alkalinity delivers the slippery, beauty-water feel on the skin that this style is known for.
Analyzed Nov 10, 2009·社団法人徳島県薬剤師会検査センター
River
MountainsSunriver Oboke sits above the Oboke (大歩危) Gorge in Tokushima, where the indoor and open-air baths look out over the river canyon and the surrounding mountains. The spring water is strongly alkaline and noticeably smooth on the skin. There is also a sauna with a cold bath. Some rooms come with a private open-air tub on the balcony, and the hotel serves local Iya Valley cuisine in the evenings.
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Irina
The promised diversity in the chat. Took a trip to Shikoku for a couple of days, stayed in the Iya Valley, where the onsens are really great. Unfortunately, work treacherously ruined all plans, but I managed to visit a couple of places. Stayed here overnight. A mediocre hotel/almost-ryokan stuck in the Showa era, with a tatami room, kaiseki, karaoke room, and gacha machines. The onsen is on the 6th floor for women and the 5th for men, they don't switch by day. The onsen is absolutely amazing, pH 9.5 - I've never encountered such "soapy" water anywhere. Like actual soap, but without the old-timers' flakes. There's a large bath with bubbles, a rotenburo with a stunning mountain view (caught the sunrise - unbelievably beautiful, but no photos unfortunately due to crowds), the fence is only on the side facing the lobby, and at the right height where you can still glimpse the view until you sit down in the bath. There's a sauna and a small mizuburo (cold bath). They also have higaeri for 700 yen, highly recommend.
Last updated June 25, 2026