Immerse yourself in free-flowing natural hot spring water and powerful löyly, surrounded by the rich nature of Mount Hongu
Aichi Toyokawa City
"Hongu no Yu" is a natural hot spring facility located at the foot of Mount Hongu in Toyokawa City, Aichi Prefecture. Its signature attraction is the three-tier bath, where you can enjoy a chloride spring that rises from deep underground. The sauna facilities are also exceptionally well equipped, and the sauna room features a powerful automatic löyly system that lets you experience an overwhelming wave of heat from the steam that bursts out all at once. The cold plunge bath is carefully temperature-controlled according to the season and conditions, sharply tightening your overheated body. The "Sky Bath" and "Forest Bath" alternate weekly for men and women, letting you enjoy restorative totonou time surrounded by lush greenery and fresh air.
TypeNatural Hot Spring
A sodium-chloride hot spring that gushes from approximately 1,000 meters underground. Rich in salt, it offers excellent heat retention and the strength of a true warming bath. You can feel its smooth, moisturizing texture on the skin. Surrounded by the breath of nature, you can surrender yourself to the blessings of this natural hot spring and spend a luxurious time that refreshes both body and mind.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity15people
The main sauna where powerful automatic löyly is performed once an hour. Water is poured all at once onto heated sauna stones, filling the room with hot steam. The intense heat stimulates the entire body and encourages remarkably refreshing sweating. Thanks to proper humidity control, it is less hard to breathe, allowing you to fully enjoy a comfortable heat. You can spend a high-quality sauna time in the quiet mountain setting.
Water QualityTap Water
Capacity5people
A cold-focused cold plunge bath that sharply tightens your body after sauna. The stable low-temperature setting of around 13°C to 15°C cools the whole body all at once and brings deep refreshment. It also has a generous depth, so you can soak in up to your shoulders and enjoy a proper cool-down. A perfect flow is in place, leading naturally to an outdoor air bath in the middle of rich nature.
Closed Days: Wednesday
1685 Kamiyamagamachi Hongushita, Toyokawa City, Aichi 441-1202
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
Immerse yourself in free-flowing natural hot spring water and powerful löyly, surrounded by the rich nature of Mount Hongu
Aichi Toyokawa City
"Hongu no Yu" is a natural hot spring facility located at the foot of Mount Hongu in Toyokawa City, Aichi Prefecture. Its signature attraction is the three-tier bath, where you can enjoy a chloride spring that rises from deep underground. The sauna facilities are also exceptionally well equipped, and the sauna room features a powerful automatic löyly system that lets you experience an overwhelming wave of heat from the steam that bursts out all at once. The cold plunge bath is carefully temperature-controlled according to the season and conditions, sharply tightening your overheated body. The "Sky Bath" and "Forest Bath" alternate weekly for men and women, letting you enjoy restorative totonou time surrounded by lush greenery and fresh air.
TypeNatural Hot Spring
A sodium-chloride hot spring that gushes from approximately 1,000 meters underground. Rich in salt, it offers excellent heat retention and the strength of a true warming bath. You can feel its smooth, moisturizing texture on the skin. Surrounded by the breath of nature, you can surrender yourself to the blessings of this natural hot spring and spend a luxurious time that refreshes both body and mind.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity15people
The main sauna where powerful automatic löyly is performed once an hour. Water is poured all at once onto heated sauna stones, filling the room with hot steam. The intense heat stimulates the entire body and encourages remarkably refreshing sweating. Thanks to proper humidity control, it is less hard to breathe, allowing you to fully enjoy a comfortable heat. You can spend a high-quality sauna time in the quiet mountain setting.
Water QualityTap Water
Capacity5people
A cold-focused cold plunge bath that sharply tightens your body after sauna. The stable low-temperature setting of around 13°C to 15°C cools the whole body all at once and brings deep refreshment. It also has a generous depth, so you can soak in up to your shoulders and enjoy a proper cool-down. A perfect flow is in place, leading naturally to an outdoor air bath in the middle of rich nature.
Closed Days: Wednesday
1685 Kamiyamagamachi Hongushita, Toyokawa City, Aichi 441-1202
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