Honsawa Hot Spring WildBath
Hot Spring Overview
Japan’s Highest Outdoor Hot Spring “Unjō no Yu” is located in Honsawa Onsen.
"Unjō no Yu" is a natural hot spring that continuously flows in the midst of untouched nature. On clear days, you can enjoy views of Mount Iō from the bath.
In addition to “Unjō no Yu,” which sits at an altitude of 2,150 meters—the highest outdoor hot spring in Japan—you can also enjoy another natural hot spring with a different mineral composition, called “Koke-momo no Yu.”
"Unjō no Yu" is a mixed-gender bath without a changing room, but wearing a swimsuit is allowed.
At the source, Honsawa Onsen, you can stay overnight in the lodge or camp in a tent.
About Secluded Rating
Access (Difficulty to Reach)
Over 1 hour walk
Scenery & Atmosphere
Untouched nature
Onsen Value
Historic unique spring
You can experience a natural, free-flowing hot spring in the heart of the wilderness.
Access is only by foot, and we have rated it a "5" for its secluded nature.
From this hot spring, it is also possible to hike to Mt. Iō (Ioudake) and Mt. Aka (Akadake) via the Honsawa Trailhead.
Honsawa Onsen is accessible only on foot.
You must drive or take a taxi to the Honsawa Entrance, and from there, it takes about 2 to 2.5 hours on foot.
There is a 4WD parking area located further in; if starting from there, it takes about 1 hour on foot to reach the hot spring.
Hot Spring Details
Practical Info
Visit Log
Bath Types
Facilities
Access Information
Recommended Routes
最寄りの高速道路（八千穂高原IC）から車
Other Routes
東京から電車
Matsubara Lake Entrance → via Matsubara Lake → Honsawa Forest Road Entrance
(In winter, even 4WD vehicles can only go this far)
→ Honsawa Forest Road (approx. 3 km)
→ Honsawa Onsen Entrance
(Even in summer, regular vehicles must stop here)
→ Yukawa Valley Hiking Trail (approx. 3 km)
→ Gate (4WD vehicles can only go this far)
→ About 1 hour on foot to Honsawa Onsen
→ About 1 hour to “Yamabiko-so”
From Koumi Station
→ About 30–40 minutes by taxi to Honsawa Onsen Entrance
From Koumi Station
→ About 30 minutes by bus to Inagoyu
→ Via Midori Pond, about 3 hours and 30 minutes on foot to Honsawa Onsen
→ About 1 hour to “Yamabiko-so”
From Chino Station
→ About 50 minutes by bus to Shibu-no-Yu
→ Approx. 2 hours hike to Kuroyuri-daira
→ Approx. 1 hour to Mt. Higashi-Tengudake
→ Approx. 1 hour 30 minutes to “Yamabiko-so”
From Chino Station
→ About 45 minutes by bus to Minoto-guchi
→ Approx. 2 hours to Akadake Kosen
→ Approx. 1 hour 30 minutes to Mt. Ioudake
→ Approx. 40 minutes to “Yamabiko-so”
From Chino Station
→ By taxi to Sakuradaira Parking Lot
→ Approx. 30 minutes to Natsuzawa Kosen
→ Approx. 50 minutes to Oren Hut
→ Approx. 20 minutes to “Yamabiko-so”
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