Reach the ultimate state of totonou with acidic spring water piped down from 1,500 m above sea level and an "iki" sauna
Fukushima Nihonmatsu City
"Dake Onsen Hinode no Sato Azumakan" is an onsen accommodation facility in Nihonmatsu City, Fukushima Prefecture. Guests can enjoy a rare acidic spring with a pH of 2.48, served straight from the source. The sauna facilities are exceptionally well equipped, with separate large public baths for men and women, plus a full-fledged sauna floor on the 7th floor featuring Japan's first installed "iki heater." From the infinity cold plunge bath with a view of Mt. Adatara to the many other features, it offers an ideal environment for sauna lovers. Surrounded by rich nature, you can spend a luxurious time that frees both body and mind.
TypeNatural Hot Spring
A nationally rare acidic spring with water piped over a distance of 8 km from a point 1,500 m above sea level on Mt. Adatara. Although it has a strong acidity of pH 2.48, the long piping process naturally mellows the water, and it is known as a skin-friendly beauty bath. Rich in metasilicic acid, the fresh water served straight from the source smooths the skin and warms you from deep within.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity10people
A calm, dry sauna located inside the separate large public bath for men and women. The crisp heat wraps around your entire body and gently eases away everyday fatigue. It is also ideal for alternating between hot spring bathing and cold bathing in the acidic spring, and its steady, comfortable heat makes it enjoyable for everyone from beginners to seasoned sauna enthusiasts.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity15people
A full-fledged sauna located in the 7th-floor observation area, equipped with Japan's first installed "iki heater." The stunning view overlooking the "true sky" is its main attraction, and the space is filled with graceful curves and the scent of wood. Löyly poured onto the sauna stones fills the room with powerful heat and humidity, creating an overwhelming sweating experience. This open and superb sauna is used while wearing swimsuits.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity8people
A sauna space in the 7th-floor observation area with two barrel saunas, "ONE SAUNA." One faces the forest, while the other lets you enjoy the space itself, allowing you to quietly work up a sweat while feeling like you are outdoors. Because it is installed indoors, it can be enjoyed comfortably year-round, offering a deeply relaxing time that lets you feel the warmth of wood and become one with the nature of Mt. Adatara.
Water QualityTap Water
Capacity4people
A cold plunge bath installed inside the large public bath with a mild temperature setting. The carefully balanced temperature is not too cold, so even those who are not good with cold baths can enjoy it comfortably. It gently cools the body after sauna use and is perfect for a relaxing time that slowly brings your heart rate back down.
Water QualityTap Water
Capacity10people
An infinity cold plunge bath in the 7th-floor observation area where you can feel united with the majestic scenery of Mt. Adatara. The sharply cold temperature quickly tightens your overheated body after sauna use. Cooling down while gazing at the vast natural landscape before you is a remarkable experience, enhanced by the extraordinary sense of openness unique to a mixed bathing area.
Closed Days: None
〒964-0074 Fukushima Prefecture, Nihonmatsu City, Dake Onsen 1-5
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
Reach the ultimate state of totonou with acidic spring water piped down from 1,500 m above sea level and an "iki" sauna
Fukushima Nihonmatsu City
"Dake Onsen Hinode no Sato Azumakan" is an onsen accommodation facility in Nihonmatsu City, Fukushima Prefecture. Guests can enjoy a rare acidic spring with a pH of 2.48, served straight from the source. The sauna facilities are exceptionally well equipped, with separate large public baths for men and women, plus a full-fledged sauna floor on the 7th floor featuring Japan's first installed "iki heater." From the infinity cold plunge bath with a view of Mt. Adatara to the many other features, it offers an ideal environment for sauna lovers. Surrounded by rich nature, you can spend a luxurious time that frees both body and mind.
TypeNatural Hot Spring
A nationally rare acidic spring with water piped over a distance of 8 km from a point 1,500 m above sea level on Mt. Adatara. Although it has a strong acidity of pH 2.48, the long piping process naturally mellows the water, and it is known as a skin-friendly beauty bath. Rich in metasilicic acid, the fresh water served straight from the source smooths the skin and warms you from deep within.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity10people
A calm, dry sauna located inside the separate large public bath for men and women. The crisp heat wraps around your entire body and gently eases away everyday fatigue. It is also ideal for alternating between hot spring bathing and cold bathing in the acidic spring, and its steady, comfortable heat makes it enjoyable for everyone from beginners to seasoned sauna enthusiasts.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity15people
A full-fledged sauna located in the 7th-floor observation area, equipped with Japan's first installed "iki heater." The stunning view overlooking the "true sky" is its main attraction, and the space is filled with graceful curves and the scent of wood. Löyly poured onto the sauna stones fills the room with powerful heat and humidity, creating an overwhelming sweating experience. This open and superb sauna is used while wearing swimsuits.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity8people
A sauna space in the 7th-floor observation area with two barrel saunas, "ONE SAUNA." One faces the forest, while the other lets you enjoy the space itself, allowing you to quietly work up a sweat while feeling like you are outdoors. Because it is installed indoors, it can be enjoyed comfortably year-round, offering a deeply relaxing time that lets you feel the warmth of wood and become one with the nature of Mt. Adatara.
Water QualityTap Water
Capacity4people
A cold plunge bath installed inside the large public bath with a mild temperature setting. The carefully balanced temperature is not too cold, so even those who are not good with cold baths can enjoy it comfortably. It gently cools the body after sauna use and is perfect for a relaxing time that slowly brings your heart rate back down.
Water QualityTap Water
Capacity10people
An infinity cold plunge bath in the 7th-floor observation area where you can feel united with the majestic scenery of Mt. Adatara. The sharply cold temperature quickly tightens your overheated body after sauna use. Cooling down while gazing at the vast natural landscape before you is a remarkable experience, enhanced by the extraordinary sense of openness unique to a mixed bathing area.
Closed Days: None
〒964-0074 Fukushima Prefecture, Nihonmatsu City, Dake Onsen 1-5
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