How we check
A room is listed only when the property says, in writing, that the bath in the room is filled with hot-spring water.
How we find the properties
We search Google Maps in Japanese for rooms with their own open-air bath (露天風呂付き客室, 客室露天風呂) and in English, across every part of each area. For Hakone, Yugawara, Ogoto Onsen, Kyoto that gave 639 ryokans and hotels.
How we check the rooms
We read each property's own website, up to 30 pages, mostly in Japanese. We could read 541 of the 639; the rest were blocked or had no site.
A room counts only when its own description says the bath uses onsen water: 温泉 (onsen), 源泉 (gensen, the source) or 天然温泉 (natural hot spring). "Open-air bath" alone is not enough. Many rooms with an outdoor tub use heated tap water while the shared baths use the spring.
Every Japanese quote on this site is copied word for word from the property's website, with a link to the page and our English translation. Our build stops if a quote can't be found in what we read.
Where the website doesn't say something (free-flowing water, the view, where dinner is served), we write "not stated".
What we can't tell you
Whether a property has changed its rooms since we read the site, or which room you will get if you book a general room type. Book the room by name and check the confirmation.
How we earn money
Booking buttons go through Stay22 to Booking.com, Agoda, Expedia or Hotels.com. If you book, we may earn a commission at no extra cost to you. Properties cannot pay to be listed or to change what we say. Affiliate disclosure.