An open-air bath on a hill with sweeping views of the Nagaoka Plain and two dry saunas
Niigata Nagaoka City
"Asonoyu Natural Hot Spring" is a day-use hot spring resort located on a hill in Nagaoka City, Niigata Prefecture. From the open-air bath, you can take in sweeping views of the Nagaoka Plain, and enjoy rich sodium-calcium chloride spring water in a spacious, open setting. The sauna complex includes two dry saunas with different temperature settings and atmospheres. You can choose between a lively space with a TV and a calm space with jazz playing, depending on your mood. The refreshing cold plunge bath, fed by underground water, and the outdoor relaxation area on the wood deck are especially soothing. With a BBQ area, foot bath, and well-equipped private rest rooms, it is a facility where you can relax and spend the whole day.
TypeNatural Hot Spring
A sodium-calcium chloride spring. Because it contains a lot of salt, the minerals left on the skin help suppress sweat evaporation, providing a lasting moisturizing effect even after you leave the bath. This is a true therapeutic spring with excellent heat retention. Although colorless and transparent, it has a faint oily aroma that lets you enjoy its authentic spring quality.
Sauna TypeDry Sauna
Stove TypeInfrared Heater
Capacity8people
A dry sauna heated by a gas far-infrared heater, characterized by strong, powerful heat. With a TV installed and a lively atmosphere, it is ideal when you want to work up a good sweat. The indoor temperature balance is excellent, allowing you to warm up deeply from the inside in a short time.
Water QualityNatural Water (Groundwater, Spring, etc.)
Capacity4people
A refreshing cold plunge bath using underground water. With a comfortable temperature setting, it gently yet surely cools you down after the sauna. The water quality is excellent and the texture is smooth on the skin, making it pleasant to soak in for a long time.
Closed Days: None
940-0806 Minamitani 2063, Asoda-machi, Nagaoka City, Niigata Prefecture
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 open-air bath on a hill with sweeping views of the Nagaoka Plain and two dry saunas
Niigata Nagaoka City
"Asonoyu Natural Hot Spring" is a day-use hot spring resort located on a hill in Nagaoka City, Niigata Prefecture. From the open-air bath, you can take in sweeping views of the Nagaoka Plain, and enjoy rich sodium-calcium chloride spring water in a spacious, open setting. The sauna complex includes two dry saunas with different temperature settings and atmospheres. You can choose between a lively space with a TV and a calm space with jazz playing, depending on your mood. The refreshing cold plunge bath, fed by underground water, and the outdoor relaxation area on the wood deck are especially soothing. With a BBQ area, foot bath, and well-equipped private rest rooms, it is a facility where you can relax and spend the whole day.
TypeNatural Hot Spring
A sodium-calcium chloride spring. Because it contains a lot of salt, the minerals left on the skin help suppress sweat evaporation, providing a lasting moisturizing effect even after you leave the bath. This is a true therapeutic spring with excellent heat retention. Although colorless and transparent, it has a faint oily aroma that lets you enjoy its authentic spring quality.
Sauna TypeDry Sauna
Stove TypeInfrared Heater
Capacity8people
A dry sauna heated by a gas far-infrared heater, characterized by strong, powerful heat. With a TV installed and a lively atmosphere, it is ideal when you want to work up a good sweat. The indoor temperature balance is excellent, allowing you to warm up deeply from the inside in a short time.
Water QualityNatural Water (Groundwater, Spring, etc.)
Capacity4people
A refreshing cold plunge bath using underground water. With a comfortable temperature setting, it gently yet surely cools you down after the sauna. The water quality is excellent and the texture is smooth on the skin, making it pleasant to soak in for a long time.
Closed Days: None
940-0806 Minamitani 2063, Asoda-machi, Nagaoka City, Niigata Prefecture
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