Sumatakyo Onsen Suikoen

Suikoen is a hot spring inn in Sumatakyo, Kawanehon Town, Haibara District, Shizuoka Prefecture, set at about 550 m elevation in the headwaters of the Oi River at the southern edge of the Southern Alps. Sumatakyo Onsen is a relatively young resort, opened in 1957 when local resident Koichi Mochizuki struck the source, and it is famed as a beautifying bath that leaves the skin smooth; the surrounding gorge is home to the scenic Yume-no-Tsuribashi (Dream Suspension Bridge) and the Sumatakyo Promenade walking trail. Suikoen is the oldest hot spring inn in Sumatakyo, dating from the opening of the spring, and its classical interior evokes the Taisho romance era with displayed artworks and antiques.

The spring is a simple sulfur spring with a source temperature of about 43 degrees Celsius and an alkaline pH of 9.18. Piped from a source roughly 4 km upstream, the large communal baths are heated, circulated with filtration, and chlorinated to protect the resource and maintain hygiene, while special rooms offer private free-flowing (kakenagashi) family baths. The water carries a faint sulfur scent and a distinctive silky texture, and is said to help with neuralgia, muscle and joint pain, sensitivity to cold, chronic skin conditions, and fatigue recovery.

The bathing facilities include indoor baths, an open-air bath, and private family baths. Day-trip bathing is available for 600 yen per adult (tax included, towel provided) from 11:30 to 20:00, though it may be unavailable when the inn is busy. Overnight stays with two meals start from roughly 10,450 yen, featuring kaiseki cuisine made with mountain and river delicacies of Oku-Oi and the local specialty wild-boar hot pot. Tel 0547-59-3100.