[Stay Blog] Staying at Ryuo Radon Onsen Hotel Yu-topia! What Is Radon? A Review with Two Meals Included

This time I stayed at Ryuo Radon Onsen Hotel Yu-topia in Kai, Yamanashi!

It’s an inn with catchphrases you rarely see elsewhere: “the hot spring you breathe in” and “a toji (hot spring cure) inn.”

Frankly, before booking, my biggest question was “what’s so great about a radon hot spring?”

In this article, as a stay blog from actually staying at Ryuo Radon Onsen Hotel Yu-topia, I review the interior, the room, the famous radon hot spring, and dinner and breakfast, using the photos exactly as I took them!

I’d be happy if this helps anyone searching “Yu-topia reviews” or “Yu-topia blog” who’s still deciding.

What Kind of Inn Is Ryuo Radon Onsen Hotel Yu-topia?

Yu-topia is a hot spring hotel in Tomitake-shinden, Kai, on the west side of the Kofu Basin.

With 35 rooms in total, it felt less like a hotel and more like an inn that still firmly keeps the air of a toji inn.

Item	Details
Official name	Ryuo Radon Onsen Hotel Yu-topia
Address	1300-1 Tomitake-shinden, Kai, Yamanashi
Phone	055-276-9111
Total rooms	35 rooms
Check-in / Check-out	15:00 / 10:00 (varies by plan)
Baths	Public bath and family bath (no open-air bath)
Bathing hours	10:00–23:00 / guests until 8:30 the next morning
Access	About 11 min on foot from Ryuo Station on the JR Chuo Main Line / about 8 min by car from Kofu-Showa IC on the Chuo Expressway
Parking	100 standard cars, free
Facilities	Restaurant, banquet hall, public bath, shop, vending machines, coin laundry (paid)

The inn’s signature is, above all, that it combines “natural radon hot spring” with “radon hot spring from a medical-grade generator.”

And it’s source-fed free-flowing (kake-nagashi), and has even received the “Pure Onsen A” certification.

Exterior and Entrance | The Roadside “Breathe-In Hot Spring, Toji Inn” Sign Is Your Landmark

First, how things looked right after arriving.

Just those two phrases, “breathe-in hot spring” and “toji inn.” So bold. My expectations went up right here.

Look up and there’s a sign along the road too!
The retro design with its distinctive mermaid illustration is great too.

The building is a maroon low-rise base topped with white guest room floors.

It shows its age, but it’s much bigger than I’d imagined, and you can sense the scale that makes it loved as a day-trip hot spring in Yamanashi too!

There’s a parking lot right nearby, and it’s free to use.

Above the entrance, boldly, “Radon Onsen.” I love how all-in this is!

The circular automatic door has a retro feel too, which is nice.

Check-in | First the Ticket Machine, Then the Front Desk

Overnight guests use the green lockers with keys.
The notice on the blue shelf says “Shoe boxes for general bathers…”

Through the automatic doors, the front counter is straight ahead.

This is where you check in. Day-trip bathers come in through the same entrance, so depending on the time it’s bustling with locals.

The room key I received after checking in had a blue keychain engraved with “Ryuo Radon Onsen Hotel,” boosting the Showa-retro hot spring trip mood!

For day-trip use, you buy a ticket at the ticket machine first.

Overnight guests could just check in at the front desk.

This banner stood prominently next to the front desk.
Apparently it took first place nationwide in the “Good Water” category of the Nifty Onsen Ranking!!

I can only expect great things!

Lobby and Interior | The Atmosphere of a Showa-Era Toji Resort Lives On

After checking in, I turned around to a sight beyond my imagination.

The interior is extremely long from side to side, with maroon carpet continuing to the back. It’s a unique space, less like a hotel lobby and more like a community center and hot spring facility combined.

Benches are scattered about, and here and there people were sitting down after their baths.

This “you can stay as long as you like” feel was very comfortable. There were plenty of reclining chairs at the back too.

The shop is lined with Yamanashi souvenirs and local sake.

Being able to finish your shopping here before checkout is quietly helpful.

There are vending machine corners at key spots, so I never had to walk far to buy a drink.

Elevator Hall | Clear Signage

Take the elevator to the guest rooms. There’s a bench in front of the elevators on the 1st floor.

The yellow arrow points to the hot spring, and peeking over, it looks quite close.

Getting off on the 2nd floor, there’s a sign to the dining room. The Showa-era hall is amazing.

You can tell this is the dinner venue, so it’s reassuring at night too.

Guest Room Corridor and Door | Room 420 This Time

This is what the guest room floor corridor looks like.

Maroon carpet runs straight to the end, and it’s quiet. I didn’t notice corridor noise even at night.

My room this time was Room 420 on the 4th floor. The door is an ordinary hotel type, and since it uses a physical key, you carry the key with you when going to the public bath.

Guest Room Report | Inside Room 420 (Western-Style Twin)

Opening the door, it was a simple, long and narrow Western-style twin room where you can see straight to the back.

It’s not showy, but it’s a “toji inn room” with everything you need properly in place.

It was well cleaned and I spent a comfortable time. The carpet looked like it had been replaced.

Between the beds are a side table and a landline phone.

Bath information and pamphlets are placed here, so what you need is gathered within reach.

Towels, a yukata, and an obi are already set on the bed. You can put these on and go straight to the public bath.

Desk Area and Storage

By the window is a space with a chair and a hanger rack.

There’s no large closet with doors; you hang things on this rack. It’s fine for one night, but for a long stay you’d want to check the number of hangers.

On the wall are a hanger hook, a mirror, and a hair dryer. Having a hair dryer in the room was appreciated after a bath.

The mirror is small, but that can’t be helped.

Room Facilities

The TV sits on a stand on the desk.

The screen is quite small, so it may be important to go in with an “as long as I can watch it” attitude.

The refrigerator was empty. You can chill things you bought at the shop or vending machines as they are, so I appreciate this setup.

An electric kettle and a tea set. Just the bare minimum tea bags that business hotels provide.

Fitting for a toji inn, time spent drinking tea slowly in the room suits it.

The air conditioner can be controlled per room. It’s fairly new and works well, which helps!

It cooled properly even in summer.

Room Plumbing | Unit Bath and Washbasin

The bath and toilet are an integrated unit type.

That said, almost nobody who stays here probably uses the room bath. The public bath is the star, so this is positioned as “handy to have at midnight.”

The washbasin is compact but at an easy-to-use height. I had no trouble brushing my teeth or washing my face.

A toothbrush and cup are provided. If you need a razor or similar, check at the front desk shop.

Shampoo and body soap are individually packaged. The public bath has them provided, so these are for the room.

At Last, the Main Event! I Tried the “Breathe-In Hot Spring” Radon Hot Spring

Now, the main purpose of coming to this inn.

Several pamphlets explaining the radon hot spring were placed in the room.

Titles like “The Toji” and “Radon Hot Springs and Health” are lined up, conveying how serious the inn is. They were interesting reading too.

How to Get to the Public Bath

Change into your yukata and head to the public bath. There are guide signs throughout.

It’s displayed together with a wall clock, so it was also handy for checking the time after the bath, thinking “dinner soon?” Follow the arrows and you won’t get lost.

The navy noren curtain is the men’s bath, and the red door is the women’s bath.

Several notices stand in front of the entrance, so first-timers will feel reassured by giving them a quick read here.

Bathing hours are from 10:00, day-trippers until 23:00, and overnight guests until 8:30 the next morning.

There’s also a notice about its effects, but how you feel varies from person to person, so go by your own impressions after actually bathing.

The changing room lockers are the “coin returned” type.

You can’t use the lockers unless you bring a 100-yen coin! Be careful.
The lockers are quite old and not very clean, a minus point.

On the bathroom wall are explanations of how the radon hot spring works and how to bathe.

The biggest feature of the radon hot spring is that, besides the usual “soaking in the hot spring and absorbing the components through your skin,” you also “inhale the radon gas that fills the room into your body by breathing.”

A radon generator fills the “radon room (bathroom)” with radon gas and ozone gas, and apparently inhaling the colorless, odorless gas raises perspiration and metabolism.

The water has a slightly thick, soft feel on the skin. It’s a little similar to Kusatsu Onsen.

While soaking, I started to sweat gradually, at a surprisingly early stage.

I felt heat building up from my core more than in an ordinary hot spring, and really felt how strong the sweating effect is!!

Radon is amazing~.

The Radon Generators Lined Up Inside Are Amazing

The real fun of this inn is actually outside the bath. There’s a sign like this in the dinner venue.

“Absorb ozone and get healthy.” It’s so direct that I laughed, but that seems to be the inn’s stance.

And in the lobby, red machines lined up in a row. The first time I saw them, I momentarily wasn’t sure where I’d come to.

The machine clearly states “Radon is sent from this device to the radon bathing and inhalation rooms.”

In other words, what’s made here is sent to the bathroom. That’s the mechanism.

Certificates are lined up above the machine, conveying how much passion has gone into this facility.

Flow meters lined up from 1 to 8. Seeing it running was a rare experience for a hot spring inn.

Even a Diploma written in English is displayed. The sheer number of certificates is impressive.

There’s also a poster saying “Make Japan’s number one hot spring.” Throughout, it was an interior that always conveyed the inn’s commitment to toji.

The water itself is source-fed free-flowing with a soft feel on the skin and nothing sharp about it. There’s no open-air bath, but it’s the type of hot spring where you soak for a long time and relax. You can bathe until 8:30 the next morning, so I fully enjoyed even a morning bath.

There’s a Coin Laundry, So Multi-Night Stays Are Easy

Fitting for a toji inn, there’s a coin laundry inside.

It’s a facility for people staying many nights. It’s also handy for trips where you want to pack light.

Dinner | Dishes Served in a Japanese-Style Dining Room

Dinner is in the dining room on the 2nd floor. The passage also had a waiting space with chairs.

The venue is a tatami room with low tables lined up.

No flashy show, but it was a calm atmosphere where you can eat slowly.

When I sat down, it was already set up like this. The sheer number of dishes got me excited!

First, the square appetizer plate. Tamagoyaki, fava beans, lemon, and vinegared dishes, colorfully and neatly arranged.

The sashimi was an assortment of salmon, sweet shrimp, tuna, and yellowtail. It’s nice that even in landlocked Yamanashi, proper sashimi comes out.

The tuna’s color looked dull and bothered me, but it was no problem at all!!

The tempura was a vegetable-focused assortment.

It would have been even better if it had been brought out freshly fried afterward! Eating it right away is the right move.

A small hot pot for each person too.

Pork, napa cabbage, tofu, and enoki. The time simmering it over solid fuel while eating was quietly happy.

The chawanmushi was smooth, with a gentle flavor topped with condiments.

A dish that lets you breathe in between.

A salad and a small dish in the nanbanzuke style topped with lemon.

It had a structure that properly slips in refreshing palate cleansers.

Last was the watermelon dessert. It was a kaiseki that satisfied through quantity and balance rather than flashiness. Frankly, I was surprised by how many more dishes there were than I’d imagined.

Breakfast | A Japanese Set Meal That Makes You Want More Rice

Breakfast the next morning is also served in the same dining room.

A Japanese set meal neatly fitted on a tray. Seeing this many small dishes lined up in the morning is delightful.

Rice and miso soup, with grilled fish, tamagoyaki, simmered dishes, and ham with salad.

It’s not flashy, but it was just the right amount after a morning bath.

When you come to Yamanashi, you’ll have hoto or a parfait for lunch, so it’s just right.

Yu-topia Reviews and Reputation Summary

Before booking, I read through reviews on each site, and the trends split cleanly. Here are the points where I thought “yes, that’s right” after actually staying.

Item	What people often say
Water	Rated very highly. Many repeat visitors come for the source-fed free-flowing water and radon bathing
Interior	Exactly the atmosphere of a Showa-era toji resort. Not for people seeking something new
Food	Many say there are many dishes and it’s good value
Staff	Many rate the service as unpretentious and friendly
Value	High satisfaction relative to the price range for hot spring and two meals

In short, it’s an inn that isn’t for people who want a “clean, new hotel,” and strikes a chord with people who want “the water and the toji experience.” If you don’t mix this up, I think satisfaction will be quite high.

3 Common Booking Mistakes

• Booking because you think there’s an open-air bath or sauna: There’s no open-air bath or sauna. It’s an inn with indoor baths only.
• Overlooking the rules for kids: Elementary and junior high school students can’t bathe on their own, and mixed bathing is only up to age 6 and 110 cm or under. Child fees apply from age 0.
• Going as if it were a resort hotel: This is a toji inn. If you expect newness of facilities, you’ll be let down.

Honest Pros and Cons

	Details
◎ Good points	Source-fed free-flowing water / the fun of being able to see the radon generators / many dishes at dinner / bathing until 8:30 the next morning / free parking for 100 cars
△ Points of concern	No open-air bath / both the interior and rooms show their age / unit bath with no separate washing area / not for people seeking a resort feel

All the downsides were things that aren’t a problem if you know about them.

On the other hand, I was more satisfied with the water than expected, so next time I’d like to visit as a day-trip bath stop.

How to Choose a Room Type

Type	Who it’s for
Western-style twin	Two guests who prefer beds. This is the type I stayed in this time, Room 420
Japanese-style room	For those who want to sleep on futons, groups, and families. Suited to a toji stay lounging on tatami
Non-smoking room	If smoke odor bothers you, request one when booking

With only 35 rooms in total, it’s safer to book early for weekends and long holidays.

How It Differs from Other Hot Spring Inns in the Kofu Area

Around Kofu there are famous hot spring areas such as Isawa Onsen and Yumura Onsen, and many nice ryokan and hotels.

Among them, Yu-topia’s position is clear: “an inn that bets everything on the water and radon bathing.”

It doesn’t compete on stylishness or views, but conversely, there are few inns that commit this fully to toji.

I think it’s the type of inn where “the water itself is the destination” rather than a base for sightseeing.

I’ve stayed at many other hotels in Yamanashi too, so if you’d like to compare, please do!

Access and Nearby Sightseeing

Route	Time needed
From Ryuo Station on the JR Chuo Main Line	About 11 min on foot
From Kofu-Showa IC on the Chuo Expressway	About 8 min by car
From Kofu Station	About 20 min by car
Parking	100 standard cars, 2 buses / free

It’s a location that pairs well with traveling by car.

It’s right by Kofu-Showa IC, so it’s easy to fit into a weekend trip from the Tokyo direction.

Shosenkyo, wineries, Takeda Shrine, and more are about 30 minutes away by car. I recommend sightseeing during the day and soaking in the water thoroughly at night and in the morning.

Booking Tips

• The plan with two meals is this inn’s main event. It would be a waste not to experience the number of dishes at dinner
• If there’s a multi-night plan, a longer toji-style stay is an interesting choice too
• Tell them your smoking or non-smoking preference when booking to be sure
• Prices and plans change by season, so check the booking site for the latest information

Dining Room Hours and Crowding

Both dinner and breakfast are in the same 2nd-floor dining room. You go at your assigned time and seats are prepared, so it isn’t crowded.

If you want to bathe in the morning before breakfast, I recommend working backward when you get up. Guests’ bathing ends at 8:30, so bath first and breakfast afterward went smoothly.

1-Night 2-Day Model Course

Time	Activity
15:00	Check-in. First, a lap exploring the interior
16:00	Radon hot spring in the public bath. Also see the radon generators inside
18:00	Kaiseki dinner in the 2nd-floor dining room
20:00	Second bath. Relax in the rest area after the bath
Next day 7:00	Morning bath (guests until 8:30)
Next day 8:00	Japanese set breakfast
Next day 10:00	Buy souvenirs at the shop and check out

Packing Checklist

• 100-yen coins (for the changing room lockers / the returned type)
• Coins for drinks (the vending machines are plentiful)
• Skincare products (room amenities are minimal)
• Laundry detergent (if using the coin laundry on a multi-night stay)

Recommendation by Travel Style

Style	Rating and reason
Solo trip / toji stay	◎ The inn’s main strength. You can focus on the water
Couples / married couples	○ Enough if you want a quiet stay. But if atmosphere matters, consider other inns
Families / with kids	△ There are age and height rules for bathing, so checking in advance is a must
Seniors	◎ Facilities and atmosphere suited to a toji stay
Girls’ trip	△ Not suited to a trip seeking stylishness

Seasonal Notes

The Kofu Basin is very hot in summer and cold in winter.

If you go in summer, I recommend limiting daytime sightseeing and spending more time relaxing with the water inside.

In winter, watch for icy roads; it’s a season when the source-fed free-flowing water that keeps you from cooling down is appreciated.

Wi-Fi, Parking, Smoking, and Pets

Item	Details
Wi-Fi	Free wireless LAN is available in all guest rooms, though the speed is slow
Parking	100 standard cars, free. Space for 2 buses too
Smoking	Non-smoking rooms available. Specify your preference when booking
Pets	Whether they’re accepted needs confirmation
Coin laundry	Inside the hotel (paid)
Shop	Yamanashi souvenirs and local sake are stocked

Satisfaction from Staying

To put it frankly, the water and radon bathing experience alone made the trip worth it.

Looking at the generators lined up inside, I thought “there’s an inn like this?” again and again, and this is a part that’s hard to convey through photos and reviews.

The rooms aren’t new but clean, and dinner had plenty of dishes.

Thanks to being able to bathe until 8:30 the next morning, I enjoyed the water three times even on a single night.

If your travel purpose is not “I want to stay somewhere clean” but “I want to soak in good water,” I think you’ll be quite satisfied with this inn.

Frequently Asked Questions

Is there an open-air bath?

No. It’s a public bath (indoor bath) setup.

What is the “breathe-in hot spring”?

The inn has equipment that sends radon into the bathroom, and the inn describes it as taking in the air along with the water while soaking. You can see the generators lined up in the corridor inside.

Can I take a day-trip bath?

Yes. Hours are 10:00–23:00, and the fee was ¥770 for adults and ¥660 for children. Please check the latest fee in advance.

Can overnight guests bathe in the morning?

Yes. The notice said overnight guests can bathe until 8:30 the next morning. I recommend taking a morning bath before breakfast.

Can I stay with kids?

Yes, but there are bathing rules. The notices said elementary and junior high school students can’t use the bath on their own, mixed bathing for children is only up to age 6 and 110 cm or under, and child fees apply from age 0.

What’s the bath in the room like?

It’s a unit bath with toilet and washbasin combined. It’s not the type with a separate washing area, so it’s best to assume you’ll use the public bath.

Is there a hair dryer in the room?

In Room 420 where I stayed, there was a wall-mounted hair dryer. It may differ by plan or room type, so check when booking if you need one.

Can I use Wi-Fi?

Free wireless LAN is available in all guest rooms.

Is parking free?

Yes. There’s room for 100 standard cars, so I think you’ll almost never have trouble with a full lot.

Can I walk from the station?

It’s about 11 minutes on foot from JR Ryuo Station. A taxi is easier with lots of luggage, but it’s a walkable distance.

Are meals served in the room?

No, you eat in the 2nd-floor dining room. It was a tatami room with low tables lined up.

Is there a coin laundry?

Yes, inside the hotel (paid). You can lighten your luggage on multi-night or toji stays.

Is there a shop?

There’s a shop near the front desk with Yamanashi souvenirs, local sake, and sweets.

Can I stay multiple nights for a toji stay?

Yes. The inn has toji as its calling card, so check the booking site for plans suited to long stays.

Are the rooms non-smoking?

Non-smoking rooms are available. If you have a preference, it’s safest to specify it when booking.

Summary | An Inn Where the Water Is the Destination

Ryuo Radon Onsen Hotel Yu-topia isn’t an inn to choose for its newness or stylishness. It’s an inn you go to for the water itself and the experience of radon bathing.

If that matches what you want, I think the satisfaction for the price is quite high. I’ll keep it on my list of candidates whenever I head toward Kofu again.

Recommended for people like this.

• People who want to soak thoroughly in good water
• People interested in toji or hot springs themselves
• People looking for an inn with an experience you can’t get elsewhere
• People traveling the Kofu area by car
• People who want to enjoy a Japanese dinner with many dishes