Kai, Yamanashi / 竜王ラドン温泉 湯ーとぴあ
Ryuo Radon Onsen Yu-topia
A hot spring in Kai that has kept its source, welling up from about 1,000 m underground, for 50 years since 1976: 100% free-flowing, with no added water, no recirculation and no chlorine, certified "Jun-Onsen A" by the Pure Onsen Association. The water is about 39 degrees. It is about 8 minutes on foot from JR Ryuo Station, for a day visit or an overnight stay.
Last official check
26 Sept 2026
Traveler reports
0
Reports open in Phase 2
Next scheduled check
25 Dec 2026
Decide before you go
A short summary made from the official facts below. Check the rows for details.
- Getting there
- Train / Car
- Closing days
- Open every day (check the notes below)
Before you go
Only facts we confirmed on official sources are shown. Anything else is marked “Not checked yet”.
- Opening hours
Day bathing 10:00-23:00; overnight 15:00-10:00.
Checked 26 Sept 2026 on the official site- Closed
Open every day.
Checked 26 Sept 2026 on the official site- Admission
Not checked yet — we have not confirmed this on an official source yet. Check with the spot before you go.
- Getting there
About 8 minutes on foot from JR Ryuo Station; about 5 minutes by car from Kofu-Showa IC (Chuo Expressway).
Checked 26 Sept 2026 on the official site- Parking
Not checked yet — we have not confirmed this on an official source yet. Check with the spot before you go.
- Payment
Not checked yet — we have not confirmed this on an official source yet. Check with the spot before you go.
- Accessibility
Not checked yet — we have not confirmed this on an official source yet. Check with the spot before you go.
Found wrong or outdated information? Let us know
Address: Kai, Yamanashi (Japanese address: 山梨県甲斐市富竹新田1300-1)
Official site: https://www.yamanashi-kankou.jp/special/pr/u-topia.html
Location
Smaller pins are other spots nearby.
Nearby spots
- No photo yetMt. AmariYamanashi13 km away (straight line)
- No photo yetGreat Cedar of ShojiYamanashi20 km away (straight line)
- No photo yetRoadside Station Nishijima Washi-no-Sato Kamisuki ParkYamanashi20 km away (straight line)
Photo: Masanori88 / Wikimedia Commons, CC BY-SA 3.0 (resized)Saiko Iyashi-no-Sato NenbaYamanashi22 km away (straight line)- No photo yetSaiko Bird Forest ParkYamanashi22 km away (straight line)
Distances are straight-line distances, not travel distances. Some locations are approximate, so treat these distances as a rough guide.
Crowds
- Crowd level
Not checked yet — no official source yet, and not enough traveler reports.
- Best time to visit
Not checked yet — no official source yet, and not enough traveler reports.
- Peak time
Not checked yet — no official source yet, and not enough traveler reports.
- Busiest days
Not checked yet — no official source yet, and not enough traveler reports.
- Busiest season
Not checked yet — no official source yet, and not enough traveler reports.
- Latest traveler report
- None yet
Traveler crowd data by time of day appears after 5 traveler reports (0 so far).
You can check typical busy hours in Google Maps ("Popular times" on the place's page). Open this spot in Google Maps
Verification log
- 26 Sept 2026First check · Tourism board · https://www.yamanashi-kankou.jp/special/pr/u-topia.htmlHours, closing days, access, description and address read from a tourism organization's site.