Ryuoh Radon Onsen Yutopia: What the “Radon Bath” Means
Plan a Yutopia visit with current admission, hours and tattoo rules. Learn how its natural spring differs from the separate radon system.
Checked: September 27, 2026
Ryuoh Radon Onsen Yutopia is not a big scenic spa. Its draw is a natural hot spring and a separate radon setup designed for bathing and inhalation. That distinction matters: “radon onsen” describes the facility’s way of using radon, not a single mineral-spring classification that can be applied to every part of the water.
Admission and practical details
| Current information | |
|---|---|
| Adult day admission, age 13+ | ¥880 |
| Children, age 12 and under | ¥770 |
| Day-bathing hours | 10 am–11 pm |
| Towel set | ¥440 extra |
| Indoor wear | ¥330 extra |
| Parking | Free; the operator lists space for 400 vehicles |
The venue is open year-round apart from maintenance or exceptional closures. Its current notice page shows no active day-use closure; the most recent 2026 women’s changing-room work limited early-morning access for about a week from August 31, a period that has passed. Check the notice page again before travelling, especially if a specific bath or early access is important.
An important operational detail: since February 2026, day visitors may not leave the property and return on the same admission. If you go out, another entry charge applies. Plan meals and errands before checking in.
Natural spring and radon equipment are separate parts of the experience
The operator describes its spring as a natural source that flows through the baths without recirculation. Yamanashi Prefecture’s tourism page gives a source temperature of about 39°C. Separately, the facility uses a radon-generating device to supply radon to the bathing environment. The spring itself and the generated radon are not the same measurement.
A 2024 report sampled water at the inlet to the men’s bath on September 3. It recorded 38.0°C at the bath inlet, a field pH of 7.8 and a laboratory pH of 8.14, with radon measured at 8.33 Bq/kg. Those readings describe that dated sample, not a guaranteed daily value or a clinical benefit. Avoid treating the source temperature, pool temperature and radon concentration as interchangeable.
Tattoos and station access
The operator’s current rule refuses entry to the shared bath for guests with tattoos, including tattoo stickers. If that applies to you, contact the venue about any possible alternative before planning around it; do not assume covering a tattoo changes the rule.
Ryuoh Station is walkable, but the venue’s own pages disagree on the time: its main access page says about eight minutes, while its FAQ says about fourteen. Allow up to 15 minutes, particularly with luggage or in hot weather, or use a taxi or local bus. By car, the operator says the bath is about three minutes from Kofu-Showa Interchange.
For a late evening soak and a specific interest in the radon setup, Yutopia is an unusual option near Kofu. If you mainly want a variety of everyday neighborhood baths instead, see the Kofu public bath guide.
