How we check

onsen pass is published by GORO Inc., a company in Tokyo. What we list comes from two places: what an onsen states on its own site, and what the onsen tells us when we ask. Every page says which of the two it was.

Three stages

1. Read what the official site statesWe record only what is stated explicitly, and keep the URL and the date we read it. Information at this stage carries a grey Official site checked mark. We never call it confirmed with the onsen.
2. Ask the onsen by email or contact formThis is the stage that matters. A written reply stays on record, and it still holds up once the staff have changed. For anything that wrecks a trip if you're turned away — tattoo policy above all — we show the vermilion Confirmed with the onsen badge only after this stage.
3. Call, as a last resortA person calls only when the official site can't be read, or when nobody replies. We never invent a booking. Our test is simple: could we describe what we did on this page without embarrassment?

Re-checking

We re-check six months after each check. Every onsen's page shows when it was last checked and when the next check is due. We don't promise anything like “checked monthly” — that is a promise we couldn't keep once there are more areas.

What we don't check

We don't check same-day availability, how busy it is, or unscheduled closures. Opening hours change too often to follow on a six-month cycle, so they sit outside what we confirm — each onsen's page links to its official site instead. Lending the word “confirmed” to something we can't follow would empty the word out. Private-bath prices are listed as they were when we checked, but they can change, so check the official site before you book.

We don't cover the water's stated health effects, indications or contraindications — please read the notices posted at the onsen. We also avoid terms with no legal definition, such as “free-flowing from the source”, because using them would mean inventing a standard of our own.

Reporting an error

If something is out of date, or simply wrong, please report it. We check, update, and change the date. Corrections from onsen operators are handled on For onsen operators (in Japanese), free of charge.

How we make money

We don't charge onsen to be listed. No onsen can pay to be included, to rank higher, or to appear larger. We may earn a referral fee when a booking goes through a booking site. Either way, we don't rewrite what we confirmed: an onsen we found says no stays a no, and we don't quietly drop it.