An ocean-view sauna overlooking the Pacific Ocean, and a bath of ancient fossil seawater
Ibaraki Oarai Town
"Oarai Shiosai no Yu" is a day-trip hot spring facility in Oarai Town, Ibaraki Prefecture. Its biggest highlight is the open-air bath, which offers a spectacular view of the Pacific Ocean right in front of you, letting you spend a luxurious time listening to the sound of the waves. You can also enjoy views of the sea from the sauna room, and the sauna experience with an ocean view is exceptional. The cold plunge bath, filled with groundwater, is wonderfully refreshing, and outdoor bathing in the open air while feeling the sea breeze brings blissful totonou. The natural hot spring is known as "ancient fossil seawater," and its rich, saline water warms the body from deep within.
TypeNatural Hot Spring
A natural hot spring with an extremely high salt concentration, known as "ancient fossil seawater." Its excellent heat-retaining effect keeps you warm long after you leave the bath. From the open-air bath, you can enjoy a panoramic view of the Pacific Ocean and savor a blissful soak along with the scent of the sea.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity15people
Powerful heat from the convection stove envelops your body, allowing you to work up a comfortable sweat while enjoying the view. It is a relaxing space where you can forget the everyday and refresh yourself in an open atmosphere.
Water QualityNatural Water (Groundwater, Spring, etc.)
Capacity2people
A refreshing cold plunge bath using groundwater. Gentle on the skin, it softly cools and tightens your body after the sauna. Fresh water continuously flows in, keeping it clean and pleasantly cool at all times.
Closed Days: None
256-25 Ōnukichō, Oarai, Higashiibaraki District, Ibaraki 311-1311, Japan
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
An ocean-view sauna overlooking the Pacific Ocean, and a bath of ancient fossil seawater
Ibaraki Oarai Town
"Oarai Shiosai no Yu" is a day-trip hot spring facility in Oarai Town, Ibaraki Prefecture. Its biggest highlight is the open-air bath, which offers a spectacular view of the Pacific Ocean right in front of you, letting you spend a luxurious time listening to the sound of the waves. You can also enjoy views of the sea from the sauna room, and the sauna experience with an ocean view is exceptional. The cold plunge bath, filled with groundwater, is wonderfully refreshing, and outdoor bathing in the open air while feeling the sea breeze brings blissful totonou. The natural hot spring is known as "ancient fossil seawater," and its rich, saline water warms the body from deep within.
TypeNatural Hot Spring
A natural hot spring with an extremely high salt concentration, known as "ancient fossil seawater." Its excellent heat-retaining effect keeps you warm long after you leave the bath. From the open-air bath, you can enjoy a panoramic view of the Pacific Ocean and savor a blissful soak along with the scent of the sea.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity15people
Powerful heat from the convection stove envelops your body, allowing you to work up a comfortable sweat while enjoying the view. It is a relaxing space where you can forget the everyday and refresh yourself in an open atmosphere.
Water QualityNatural Water (Groundwater, Spring, etc.)
Capacity2people
A refreshing cold plunge bath using groundwater. Gentle on the skin, it softly cools and tightens your body after the sauna. Fresh water continuously flows in, keeping it clean and pleasantly cool at all times.
Closed Days: None
256-25 Ōnukichō, Oarai, Higashiibaraki District, Ibaraki 311-1311, Japan
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