Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesSodiumCalcium
Perched along the Pacific shore of the Kii Peninsula, Susami Onsen offers thermal bathing enhanced by invigorating ocean breezes and panoramic sea views characteristic of this dramatic Wakayama coastline. The mineral waters draw from deep underground veins warmed by subterranean heat, providing a natural reprieve for visitors who explore the nearby Cape Shionomisaki—the southernmost tip of Honshu—and the surrounding marine reserve famed for diving. Susami's small-town atmosphere, rich fishing heritage, and coastal onsen culture embody the quiet authenticity of Kii Peninsula spa life away from more crowded resort towns.
Insider tip — Susami is a tiny fishing village on the Kii coastline where bicarbonate springs emerge close enough to the sea that some outdoor baths offer unobstructed views of emerald coves below. The soft alkaline water is prized locally for soothing sunburned skin after snorkeling in Susami's world-renowned underwater mailbox. Weekdays see almost no tourists, granting near-private access to tatami rest rooms and seasonal kaiseki meals. Arrive by the Kisei rail line and walk ten minutes through orange groves to the bathhouse.
