♨️Ryokan with outdoor baths worth booking a year out

Private or scenic rotenburo only, not just 'has an onsen'. Booking calendars open early, plan ahead.

01
Tsurunoyu Onsen (Nyuto Onsen, Akita)
the milky blue mixed bath is the famous one. book the ryokan itself a year out for snow season, off-peak weekdays are more realistic
02
Kuroyu Onsen (Nyuto Onsen, Akita)
quieter, more rustic neighbor to Tsurunoyu in the same valley. no fancy website so call ahead
03
Takaragawa Onsen Osenkaku (Minakami, Gunma)
04
Sekizenkan (Shima Onsen, Gunma)
the Mori no Yu open-air bath, honkan building dates to 1691. day-trippers get the Roman-style Genroku bath instead
05
Yamabiko Ryokan (Kurokawa Onsen, Kumamoto)
06
Kounoyu (Kurokawa Onsen, Kumamoto)
buy the Nyuto Tegata pass for ¥1,500, hop between three rotenburo instead of committing to one ryokan. bring an IC card for the train

Or start a list of your own. Free, it takes a minute.