Hakuba Happo Onsen is a hot spring destination at the foot of the Japanese Alps in Hakuba Village, Nagano Prefecture. Set amid clear air and mountain scenery that changes with the seasons, it invites visitors to enjoy a relaxing soak alongside outdoor sightseeing. The spring rises from an area of serpentine rock and is known for its unusually high alkalinity, with a pH above 11. The site describes it as Japan’s only natural hydrogen hot spring and highlights its smooth, silky feel, which visitors associate with soft, refreshed skin.

The destination offers four day-use bathing facilities: Happo no Yu, Mimizuku no Yu, Obinata no Yu, and Sato no Yu, as well as two footbaths. Hot spring water is also supplied to local inns. Guests can enjoy food and souvenirs, including hot spring ramen made with noodles kneaded using the mineral water and traditional onsen manju sweets. Facility hours and seasonal operating periods vary.