Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
SoufreSulfuresSulfates
Komagatake Onsen in Nanae, Hokkaido, lies at the foot of the majestic Komagatake volcano, whose symmetrical cone dominates the southern skyline of the Oshima Peninsula. Sodium-sulphate spring waters emerge here with a mild, slightly tangy character believed to ease skin ailments and respiratory complaints common in Hokkaido's cold winters. Local fishing families have historically used these baths to warm themselves after long days on Funka Bay, preserving a working-class onsen tradition distinct from more polished resort destinations.
Insider tip — Komagatake onsen sits in the shadow of the twin-peaked Mount Komagatake stratovolcano on Hokkaido's Oshima Peninsula, where sulfurous waters at 42°C reflect the mountain's active geothermal system. The volcano last erupted significantly in 1929 and 1996, and its rugged silhouette dominates the skyline from the bath. Hakodate city is nearby, making this a natural extension of a Hakodate cultural trip. The sulfur content is high enough to produce a distinctly yellow tinge in older basin stone, a visible testament to the water's volcanic origin.