A blissful retreat surrounded by a highly concentrated private hot spring source rising from 1,330 meters underground and the underground waters of Mt. Fuji
Shizuoka Numazu City
"Suruga no Yu Sakaguchiya" is a day-use hot spring facility in Numazu City, Shizuoka Prefecture, boasting 100% of its own natural hot spring source. The sodium-calcium chloride spring that rises from 1,330 meters underground is an extremely mineral-rich "warming bath" with a total dissolved solids content of over 10,000 mg/kg. It uses a unique sterilization system that does not rely on chlorine, so you can fully enjoy the true freshness and fragrance of the hot spring. The sauna area includes a full-fledged dry sauna as well as a sauna using binchotan charcoal. In addition, the cold plunge bath, generously fed with free-flowing spring water from Mt. Fuji’s underground stream, offers the superb feel and refreshing clarity unique to natural water, leading you to the ultimate state of perfect relaxation.
TypeNatural Hot Spring
A sodium-calcium chloride spring. With a total dissolved solids content exceeding 10,000 mg/kg, it is an exceptionally highly concentrated bath with excellent moisturizing and heat-retention effects. You can enjoy the fresh natural source water as it rises from 1,330 meters underground, without any added water, and it slowly loosens and relaxes your body from deep within.
Sauna TypeDry Sauna
Stove TypeInfrared Heater
Capacity7people
A dry sauna with far-infrared heaters that powerfully warm you deep to your core. The stable heat circulates throughout the room, encouraging high-quality sweating. In the calm, softly lit space, you can relax and refresh while watching TV.
Water QualityNatural Water (Groundwater, Spring, etc.)
Capacity2people
A cold plunge bath that lavishly uses underground water, one of Mt. Fuji’s abundant gifts, in a free-flowing system. It has a crisp coolness around 15°C, yet the natural water gives it an astonishingly soft touch on the skin. With a refreshing sensation that wraps your whole body, you can enjoy the ultimate rejuvenating experience.
Closed Days: None
1265-3 Okamiya, Numazu-shi, Shizuoka 410-0011
Gender Access
Gender Separated
Curated by an expert who visits onsen and sauna facilities every day and has explored 300+ locations — only facilities confirmed to be truly exceptional are featured.
Learn more
A blissful retreat surrounded by a highly concentrated private hot spring source rising from 1,330 meters underground and the underground waters of Mt. Fuji
Shizuoka Numazu City
"Suruga no Yu Sakaguchiya" is a day-use hot spring facility in Numazu City, Shizuoka Prefecture, boasting 100% of its own natural hot spring source. The sodium-calcium chloride spring that rises from 1,330 meters underground is an extremely mineral-rich "warming bath" with a total dissolved solids content of over 10,000 mg/kg. It uses a unique sterilization system that does not rely on chlorine, so you can fully enjoy the true freshness and fragrance of the hot spring. The sauna area includes a full-fledged dry sauna as well as a sauna using binchotan charcoal. In addition, the cold plunge bath, generously fed with free-flowing spring water from Mt. Fuji’s underground stream, offers the superb feel and refreshing clarity unique to natural water, leading you to the ultimate state of perfect relaxation.
TypeNatural Hot Spring
A sodium-calcium chloride spring. With a total dissolved solids content exceeding 10,000 mg/kg, it is an exceptionally highly concentrated bath with excellent moisturizing and heat-retention effects. You can enjoy the fresh natural source water as it rises from 1,330 meters underground, without any added water, and it slowly loosens and relaxes your body from deep within.
Sauna TypeDry Sauna
Stove TypeInfrared Heater
Capacity7people
A dry sauna with far-infrared heaters that powerfully warm you deep to your core. The stable heat circulates throughout the room, encouraging high-quality sweating. In the calm, softly lit space, you can relax and refresh while watching TV.
Water QualityNatural Water (Groundwater, Spring, etc.)
Capacity2people
A cold plunge bath that lavishly uses underground water, one of Mt. Fuji’s abundant gifts, in a free-flowing system. It has a crisp coolness around 15°C, yet the natural water gives it an astonishingly soft touch on the skin. With a refreshing sensation that wraps your whole body, you can enjoy the ultimate rejuvenating experience.
Closed Days: None
1265-3 Okamiya, Numazu-shi, Shizuoka 410-0011
Gender Access
Gender Separated
Curated by an expert who visits onsen and sauna facilities every day and has explored 300+ locations — only facilities confirmed to be truly exceptional are featured.
Learn more