Onsen is not sauna, but onsen culture and sauna culture meet at the same temperature, with the same reverence for water and stone. Our 9 Japanese Curator's Picks span Beppu's eight-circles thermal city, Hakone's mountain ryokan, Naoshima's contemporary-art bathhouse, and the new wave of urban Tokyo saunas.
"Hadaka no tsukiai. Naked friendship. The Japanese phrase for the candor that emerges between bathers in an onsen."
Japan sits on a tectonic furnace. Every island has hot springs, every prefecture has its onsen brand, every village has at least one bathhouse the locals would die before letting close. Volcanic heat, mineral chemistry, and a thousand years of bathing etiquette converge here in a way no other country has matched.
Our gold list privileges the historically continuous places (Beppu, Hakone, Kusatsu) and the architecturally significant ones (SAZAE on Naoshima, From P in Hakuba, JIKON in Tokyo). Some onsen require a stay at the ryokan that owns them; those access notes are clear on each venue page.
Each card below links to a full venue page with hours, access notes, type, and editorial context. Cards are ordered alphabetically.
Over 2,000 hot springs in one city — the most of any city in the world. Features mud baths, sand baths, steam baths, and medicinal baths.
The oldest onsen in Japan, in continuous use since the 6th century. The 1894 Dogo Onsen Honkan is a Tangible Cultural Property and the inspiration for the bath house in Spirited Away.
A glamping site combining a barrel sauna with dome tents (integrated stove systems) and outdoor structures for cooling and rest. Featured in CN Traveller's 'World's Most Beautiful Saunas'.
A Saunasto Curator's Pick in the country. Type: onsen. Access: public.
Mountain onsen town between Tokyo and Mount Fuji. Variety of mineral-rich springs, traditional ryokan inns, and lake views.
Rooftop Finnish-style sauna atop Hakuba Highland Hotel with full panoramic view of the Northern Alps.
Saunachelin 2025 #2. The urban sauna of the future with five saunas, three water baths, and theatrical steam performances.
Famously authentic mountain onsen town in the Aso highlands. The 28 ryokan share a rotenburo (outdoor-bath) ticket so visitors can sample three baths in a single day.
Japan's #1 ranked onsen for 15 consecutive years. Famous yubatake (hot water field) in the town center. Strong sulfur-rich waters.
Hokkaido's most famous onsen with 9 types of thermal water. Jigokudani (Hell Valley) volcanic landscape.
Saunachelin 2025 #2. The urban sauna of the future with five saunas, three water baths, and theatrical steam performances.
Designed by Kengo Kuma & Associates with interiors by Japanese sauna collective TTNE; named after the sazae, a conical sea snail native to Japan. Part of Naoshima's contemporary art programme.
Saunachelin 2025 #5. Tokyo's urban wellness escape in Meiji Park with multiple saunas and herbal infusion baths.
Hot-spring resort town under Mt. Yufu in northern Kyushu. Known for design-led ryokan, contemporary art galleries, and morning mist photographs.
Saunasto's gold list spans 27 countries. Browse another, or jump to the global index.
The iOS app is free. Curator's Picks are highlighted. Pro adds proximity alerts when you're near a saved venue.