Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesSodiumCalcium
Kasado Onsen is located in Kudamatsu City, Yamaguchi Prefecture, near Kasado Island in the Seto Inland Sea — an area where maritime industrial heritage, including one of Japan's major shipbuilding facilities, coexists with the natural beauty of the Inland Sea islands. The siliceous thermal waters here serve the Kudamatsu community as a gathering place for relaxation amid a landscape where industrial modernity and island sea scenery create a distinctively western Japanese industrial coast aesthetic. This onsen provides an authentic local bathing experience in a Yamaguchi coastal community where the Inland Sea's maritime culture and industrial history have shaped a unique regional identity.
Insider tip — Kasado Onsen draws bicarbonate-rich thermal water in the Aichi Prefecture region of central Honshu, a heavily industrialised area where small onsen facilities serve as essential retreats from urban life. The smooth alkaline waters are valued for their skin-softening properties after long days in the city. Despite the industrial surroundings, the baths maintain a traditional atmosphere with cypress wood tubs and seasonal garden views. Nagoya's culinary scene, famous for miso katsu and hitsumabushi eel rice, is within easy reach.
