A rare sand-and-salt bath and an exceptional detox experience with the facility’s own spring, the closing bath
Gunma Annaka City
"Megumi no Yu" is a day-use hot spring facility in Isobe Onsen in Annaka City, Gunma Prefecture. Its sodium-chloride and sodium bicarbonate strong saline spring, gushing up from deep underground, is beloved as the closing bath for its gently enveloping texture on the skin. It also features a rare sand-and-salt bath, available in very few places nationwide, offering a one-of-a-kind detox experience where you can work up a sweat slowly under the weight of raw salt and sand. The saunas consist of two types, a far-infrared sauna with automatic löyly and a steam sauna, offered in alternating use for men and women. Together with the soft-water cold plunge bath, this facility lets you refresh deeply in both body and mind amid the quiet atmosphere of a hot spring town.
TypeNatural Hot Spring
A sodium-chloride and sodium bicarbonate strong saline spring gushing up from underground. With its high salt content, it offers both powerful heat retention and skin-beautifying effects. The light brown water feels extremely smooth on the skin, and after bathing, its comforting warmth lingers for a long time. In the all-weather outdoor bath, you can fully savor the power of this renowned spring in an open, spacious setting.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity12people
A full-fledged far-infrared sauna equipped with an automatic löyly function. With löyly performed every 10 minutes, the room is always filled with just the right level of humidity and comfortable heat. It warms you slowly from deep within the body and encourages a high-quality sweat. In a calm space with the warmth of wood, you can spend time quietly facing yourself.
Sauna TypeSteam Sauna
Capacity6people
A steam sauna where fine mist gently envelops the whole body. With a temperature setting that even those who do not like high-heat saunas can comfortably enjoy, you can work up a sweat while keeping your skin moist. The heat of the steam makes breathing easier and helps release both physical and mental tension. It offers a gentle relaxation time, different from a dry sauna.
Water QualityTap Water
Capacity3people
A cold plunge bath that gently cools down your heated body after the sauna. The temperature is set a little on the higher side, so it is not too cold and can be enjoyed with a slow soak. The water is soft and less irritating to the skin, making it easy for beginners to relax and cool down with confidence. In the calm atmosphere of a hot spring town, you can refresh yourself with a pleasant sense of lightness.
Closed Days: None
3-3-41 Isobe, Annaka City, Gunma Prefecture 379-0127
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
A rare sand-and-salt bath and an exceptional detox experience with the facility’s own spring, the closing bath
Gunma Annaka City
"Megumi no Yu" is a day-use hot spring facility in Isobe Onsen in Annaka City, Gunma Prefecture. Its sodium-chloride and sodium bicarbonate strong saline spring, gushing up from deep underground, is beloved as the closing bath for its gently enveloping texture on the skin. It also features a rare sand-and-salt bath, available in very few places nationwide, offering a one-of-a-kind detox experience where you can work up a sweat slowly under the weight of raw salt and sand. The saunas consist of two types, a far-infrared sauna with automatic löyly and a steam sauna, offered in alternating use for men and women. Together with the soft-water cold plunge bath, this facility lets you refresh deeply in both body and mind amid the quiet atmosphere of a hot spring town.
TypeNatural Hot Spring
A sodium-chloride and sodium bicarbonate strong saline spring gushing up from underground. With its high salt content, it offers both powerful heat retention and skin-beautifying effects. The light brown water feels extremely smooth on the skin, and after bathing, its comforting warmth lingers for a long time. In the all-weather outdoor bath, you can fully savor the power of this renowned spring in an open, spacious setting.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity12people
A full-fledged far-infrared sauna equipped with an automatic löyly function. With löyly performed every 10 minutes, the room is always filled with just the right level of humidity and comfortable heat. It warms you slowly from deep within the body and encourages a high-quality sweat. In a calm space with the warmth of wood, you can spend time quietly facing yourself.
Sauna TypeSteam Sauna
Capacity6people
A steam sauna where fine mist gently envelops the whole body. With a temperature setting that even those who do not like high-heat saunas can comfortably enjoy, you can work up a sweat while keeping your skin moist. The heat of the steam makes breathing easier and helps release both physical and mental tension. It offers a gentle relaxation time, different from a dry sauna.
Water QualityTap Water
Capacity3people
A cold plunge bath that gently cools down your heated body after the sauna. The temperature is set a little on the higher side, so it is not too cold and can be enjoyed with a slow soak. The water is soft and less irritating to the skin, making it easy for beginners to relax and cool down with confidence. In the calm atmosphere of a hot spring town, you can refresh yourself with a pleasant sense of lightness.
Closed Days: None
3-3-41 Isobe, Annaka City, Gunma Prefecture 379-0127
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