Enjoy a natural-water sauna and shioyu in Otsuchi, the town of spring water
Iwate Otsuchi Town
"Masto no Yu" is a day-use bath facility in Otsuchi Town, Iwate Prefecture. It makes lavish use of the pure natural water of Otsuchi, a town known for its abundant spring water, and its Finnish-style auto löyly sauna and icy cold plunge bath with a depth of 140 cm have earned strong support from sauna enthusiasts. With a wide variety of baths, including "shioyu" drawn from a well near Otsuchi Bay, a high-concentration artificial carbonated spring, and an open-air hot bath, it is a space where you can refresh both body and mind while feeling the blessings of Sanriku’s natural environment.
TypeSpecialty Bath
A bath using natural water drawn from a private well near Otsuchi Bay, rich in salt and minerals. It is expected to offer benefits similar to seawater bathing and is said to be good for preventing colds and promoting health. This unique hot water lets you feel the bounty of the Sanriku sea while warming you to the core.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity15people
A full-fledged Finnish-style dry sauna. Auto löyly is carried out every hour, and soothing steam scented with a different aroma each day fills the room. Powerful heat encourages deep sweating, helping wash away daily fatigue along with impurities, making this a sauna space that satisfies even serious sauna lovers.
Water QualityNatural Water (Groundwater, Spring, etc.)
Capacity3people
A cold plunge bath filled with pristine natural water unique to Otsuchi, the town of spring water, drawn from a private well on the property. With a very deep water depth of 110 to 140 cm, its greatest feature is the ability to cool the entire body quickly and evenly. Its crisp coldness and mellow water quality guide you into blissful totonou.
Closed Days: None
43-16 Omachi, Otsuchi Town, Kamihei District, Iwate 028-1112
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
Enjoy a natural-water sauna and shioyu in Otsuchi, the town of spring water
Iwate Otsuchi Town
"Masto no Yu" is a day-use bath facility in Otsuchi Town, Iwate Prefecture. It makes lavish use of the pure natural water of Otsuchi, a town known for its abundant spring water, and its Finnish-style auto löyly sauna and icy cold plunge bath with a depth of 140 cm have earned strong support from sauna enthusiasts. With a wide variety of baths, including "shioyu" drawn from a well near Otsuchi Bay, a high-concentration artificial carbonated spring, and an open-air hot bath, it is a space where you can refresh both body and mind while feeling the blessings of Sanriku’s natural environment.
TypeSpecialty Bath
A bath using natural water drawn from a private well near Otsuchi Bay, rich in salt and minerals. It is expected to offer benefits similar to seawater bathing and is said to be good for preventing colds and promoting health. This unique hot water lets you feel the bounty of the Sanriku sea while warming you to the core.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity15people
A full-fledged Finnish-style dry sauna. Auto löyly is carried out every hour, and soothing steam scented with a different aroma each day fills the room. Powerful heat encourages deep sweating, helping wash away daily fatigue along with impurities, making this a sauna space that satisfies even serious sauna lovers.
Water QualityNatural Water (Groundwater, Spring, etc.)
Capacity3people
A cold plunge bath filled with pristine natural water unique to Otsuchi, the town of spring water, drawn from a private well on the property. With a very deep water depth of 110 to 140 cm, its greatest feature is the ability to cool the entire body quickly and evenly. Its crisp coldness and mellow water quality guide you into blissful totonou.
Closed Days: None
43-16 Omachi, Otsuchi Town, Kamihei District, Iwate 028-1112
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