It was selected for the “Nifty Hot Springs: Top 100 Hot Springs 2026” list.

“Ryūō Radon Onsen Yutopia,” operated by Yutopia Co., Ltd. (Location: Kai City, Yamanashi Prefecture; Representative Director: Yoshiteru Hayakawa), has been selected for *Nifty Onsen: 100 Best Hot Springs 2026*, the new definitive guide to choosing hot springs and super sentō.

To be honest, this hot spring isn’t the kind of glamorous spot that appeals to everyone.

It is neither a large-scale spa competing with the latest facilities nor a tourist attraction lined with Instagram-worthy displays. However, for those who love the water itself, want to experience its unique properties, and wish to quietly reconnect with their bodies, it will be an unforgettable experience.

Radon Hot Spring

Radon Inhalation Room

■ What is “Top 100 Hot Springs 2026”?

This is a prestigious award presented to the top 100 establishments in the hot spring industry, carefully selected from among Japan’s renowned hot spring facilities to include both “rising stars” set to lead the next generation and historic “legendary establishments.” Our facility has been selected as one of the “Legendary Establishments” in the “Top 100 Hot Springs 2026”!

▼ Click here for the Nifty Onsen “Top 100 Hot Springs 2026” special website

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▼Click here for our hotel’s profile page on Nifty Onsen

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We owe this prestigious award—selected from among so many hot springs—entirely to all of you who have always loved and supported Yu-Topia. The entire staff would like to express our heartfelt gratitude.

Selected for Nifty Hot Springs: Top 100!

[Ryuo Radon Hot Spring Yu-Topia] Click here to book your stay

[Part 3 of Our 80th Anniversary Celebration] Special Discounts Now Available!

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You might be thinking, “A hot spring in the heat of summer?” but actually, summer is when radon hot springs really shine!

● A Hot Spring You “Breathe In” Efficiently

By slowly inhaling the steam, you can recharge your energy from the inside out—perfect for bodies feeling the effects of summer fatigue!

● Powerful Ionization from Alpha Rays

Also known as ionization, radon’s ionizing effect warms you deeply from the inside out.

● Surprisingly Smooth Skin After Your Bath

Even though you’ll feel thoroughly warmed, your skin won’t feel sticky after your bath—it’s mysteriously refreshing and light!

Why not come and wash away your daily fatigue in our prized waters, selected as one of the “100 Famous Hot Springs”?

Top 100 Hot Springs 2026

■ “Ryuo Radon Hot Spring Yu-Topia,” Kai City, Yamanashi Prefecture

For 50 years since Showa 51, we have continued to protect this spring, which bubbles up from a depth of approximately 1,000 meters underground.With no added water, no recirculation, and no chlorine, this is a genuine “100% free-flowing spring water.” Certified as “Pure Hot Spring A”—the highest rank by the Pure Hot Spring Association—it is an extremely rare and renowned hot spring, one of only a limited number (*) in the entire country.

(*There are 93 facilities certified as “Pure Hot Spring A” nationwide as of 2026.)

Even at this very moment, water flowing directly from the earth is being poured into the baths. The spring temperature is approximately 39 degrees. The appeal lies not in the intensity of the heat, but in the comfort of surrendering yourself to the gentle waters and warming up slowly.

Furthermore, fresh radon is fed into the bathing area via a dedicated system, offering a unique bathing experience where you “inhale the hot spring” along with the rising steam. Within about 5 to 10 minutes, sweat begins to beek from your entire body, and many visitors report feeling a deep warmth distinct from that of a sauna.

A Certified “Pure Hot Spring” with Free-Flowing Water

■ The hydrogen-rich hot spring water has also earned “Beautiful Skin Certification”!

The spring source boasts strong reducing properties, with an “ORP of -270 millivolts” that demonstrates remarkable antioxidant power. Due to the overwhelming power of this water, it has long been affectionately known within the facility as “Miracle Life Water®.”

Furthermore, based on research into hot springs and skin science conducted by POLA ORBIS Holdings, Inc., it has been certified as a “Melting Purifying Hot Spring.” We are also proud of our “Moisture and Luster Bath,” which leaves your skin feeling as soft and smooth as if you were enveloping your entire body in a facial toner.

*ORP (Oxidation-Reduction Potential) is an indicator that prevents substances from rusting. While ordinary tap water has a positive ORP value, a reading of -270 mV is proof of overwhelming freshness and an extremely strong ability to prevent oxidation of the skin and body.

Certified Beauty Hot Spring

The building retains a nostalgic Showa-era atmosphere and cannot compete with famous hot spring resorts in terms of luxury or modernity. Nevertheless, it has earned the support of hot spring enthusiasts nationwide thanks to the feel of the skin after bathing, the warmth that lingers deep within the body, and the power of the water that makes you think, “I want to soak in it again.”

It is a true standout, having been awarded first place nationwide in the 2024 Nifty Onsen “Hot Spring Super Sento Ranking” and selected as the national champion in the “Best Water Quality” category for two consecutive years.

It’s about an 8-minute walk from JR Ryuo Station and about a 5-minute drive from the Kofu-Showa Interchange on the Chuo Expressway. You can enjoy it whether you’re visiting for the day or staying overnight to soak in the waters multiple times on a therapeutic hot spring retreat.

Panoramic View 1

Panoramic View 2

■For those seeking authenticity rather than flashiness.

Ryuo Radon Hot Spring, a one-of-a-kind hot spring that Yamanashi is proud to call its own, is the ultimate destination for hot spring enthusiasts. Even if you just stop by while sightseeing, you’ll feel the difference the moment you step into the bath: the scent of the water, its gentle feel on your skin, and the warmth that quietly washes over you.

Add a rejuvenating soak to your Yamanashi trip as you explore Mount Fuji, Shosenkyo Gorge, and local wineries. This spring—which has remained true to its roots for half a century,不受流行趋势影响—is sure to transform your Yamanashi journey into a deeper, more memorable experience.

Here you’ll find an authentic hot spring experience unique to Yamanashi.

■Facility Information

Facility Name: Ryuo Radon Hot Spring Yu-Topia

Address: 1300-1 Tomitake-Shinden, Kai City, Yamanashi Prefecture

Phone Number: 055-276-9111

Hours: Day-use hot springs 10:00 AM–11:00 PM / Overnight stays 3:00 PM–10:00 AM

Closed: Open year-round

Admission Fee: Adults 880 yen / Children 770 yen

Accommodation Rates: Room only: 8,800 yen and up / Room with two meals: 13,200 yen and up