The baths where everyone shares the water
Several of the onsen most worth travelling for — Sukayu’s thousand-person hall, Takaragawa’s river baths, Tsurunoyu in Nyuto — are mixed-gender. That is not a fringe curiosity, it is how these particular baths have always worked, and it catches visitors out because nothing on the way in says so in English. Here is where it applies, what you may wear, and where there are women-only hours.
What you can wear is not the same everywhere
This is the part that surprises people. At Takaragawa a bathing garment is required and included in the price, and you may not bring your own. At Hoshi Onsen the opposite holds: no garment, no towel in the water. Getting it wrong is awkward in both directions, so we record each one separately.
With women-only hours
Where the bath is reserved for women at set times, taken from the facility’s own notice.
Takaragawa Onsen Osenkaku
Four huge riverside open-air baths built out of boulders along the Takaragawa, about 470 tatami mats of water in total. THREE OF THEM ARE MIXED BATHING: Kodakara-no-yu (200 tatami, with a Ho…
Hoshi Onsen Chojukan
Hoshi-no-yu, built in 1895, is one of the few ashimoto-yushutsu baths in Japan - the water rises through the gravel floor of the tub itself, so it reaches you without ever touching the air. …
Niseko Grand Hotel
The signature bath is a large mixed-gender garden open-air bath; a bathing garment (yuami-gi) is worn and is included in the day-use price, with rentals also listed for women and men. There …
Jigokudani Onsen Korakukan
MIXED-GENDER open-air bath on the riverbank, facing the Jigokudani geyser. This is the bath in the famous photographs, and it is konyoku - men and women share it. The inn does not state any …
Shinzanso
MIXED-GENDER open-air bath in three tiers beside the Gamata River, the largest of the pools. Swimsuits and bath towels are explicitly allowed in it, which is unusual and makes it approachabl…
Sukayu Onsen Ryokan
The Hiba Sennin-buro ('thousand-person bath') is a 160-tatami hall built entirely of hiba cypress with no supporting pillars, holding four different source waters (Netsu-no-yu, Hie-no-yu, Sh…
Aoni Onsen (Lamp no Yado)
Kenroku-no-yu is open 24 hours and the women's side has its own open-air tub, so women can avoid the mixed bath entirely.
Ganiba Onsen
'Karako-no-yu', the mixed open-air bath, sits 50 m from the main building in virgin forest - you walk out to it. The inn sets a women-only slot of 19:30-20:30, which falls after day-use hour…
Namari Onsen Fujisan Ryokan
Hakuen-no-yu, the reason people come: a rock bath averaging 1.25 m deep that you stand up in, with the spring rising through the floor of the tub itself. It is mixed bathing, with women-only…
Osawa Onsen
Osawa-no-yu, the big open-air bath on the riverbank under the old wooden buildings, is mixed. Women-only every day 20:00-21:00. The inn's FAQ explicitly refuses swimsuits and bath towels in …