Looking into Ancient Hotel Asama Karuizawa

I've been working through a series where I look into campsites, day-trip hot springs, and inns one at a time. This time I picked a place in Karuizawa as a “detour stop” for a hotel staycation, the kind where the hotel itself is the destination.

The place I looked into is Ancient Hotel Asama Karuizawa. I'm an indoor person, and I have a driver's license but I'm a paper driver who never actually drives. Even so, a small hotel where I could take it easy inside caught my eye, so I went through the official site page by page.

The Short Version

It's a small hotel with only 13 rooms, and every stone in the large public bath is a “crystal stone,” so it seems like a place that really puts effort into the time you spend inside.
As for Rakuten Mobile signal, the official tool didn't show a result, so the answer is unknown.

I've put the details below.

What Kind of Place Is Ancient Hotel Asama Karuizawa?

It's a hotel in the town of Karuizawa, in Kitasaku District, Nagano Prefecture. The story page on the official site says “2011, in Karuizawa's national park.” The concept is “renewal of the heart, and refreshment,” and it seems to emphasize the kind of hospitality only a small hotel can offer.

Here is the basic information, as far as I could tell from the official site.

Rooms: 13 in total, and apparently each room is named after a mineral
Booking: there's an online reservation page, and it looks like it uses an external booking system
Check-in and check-out times: I couldn't find them on the official site
Room rates: I didn't find anything like a price list

For the details, it's safest to check the official site.

Komorin

I love that every room is named after a mineral. Just looking through the names made me feel a little like I was traveling.

A Slightly Unusual Bath Where Every Stone Is a “Crystal Stone”

The thing that stood out most to me was the large public bath, called Hibiki no Yu (the “Bath of Echoes”). The official site says that all the stones in the bath are “crystal stones.” Apparently the official explanation is that this stone emits far-infrared rays and gives off radon, a component found in therapeutic spring water.

Hours: 6:00-10:00 and 15:00-24:00
Bathing tax: apparently charged separately per night for guests aged 12 and over, but I couldn't find the amount
Children bathing together: it seems to say up to age 6
Family bath (private): reservation-based, and it looks like you ask at the front desk. The hours are the same as the large bath, 6:00-10:00 and 15:00-24:00

I couldn't confirm the spring quality, the effects, whether there's a sauna, or whether day-use bathing is available on the official site. The same goes for the family bath fee and the time limit per group. From what I saw on the room pages, it doesn't look like any room is explicitly described as having a hot spring or an open-air bath.

A Look at the 13 Rooms Named After Minerals

The room page lists Nos. 01-13, and they seem to come in a mix of Japanese-style, Western-style, and combined Japanese-Western types. Here are a few that caught my eye.

Amber Room: Japanese-style, 36.30 m², sleeps 1-4
Malachite Room: Japanese-Western, 36.03 m², sleeps 1-2. It's described as having a hearth
Lapis Lazuli Room: Japanese-Western, 36.30 m², sleeps 1-3. The tatami area seems to have a sunken kotatsu
Fluorite Room: Western-style, 52.54 m², sleeps 1-3. It mentions a rotating fireplace
Garnet Room: Western-style, 38.12 m², sleeps 1-2. It has a fireplace, and the description also uses the words “semi-open-air bath”
Jade Room: Japanese-Western, 73.06 m², the largest, sleeps 3-7, and apparently has a loft
Feldspar Room: Western-style, 24.39 m², the most compact, and it seems to sleep 1-2

There's also a room that shares its name with the stones in the large bath, the Crystal Stone Room. Each of the 13 rooms has its own character, so I got the impression you could spend a good while just choosing a room.

Meals, a Garage, and a Stay That Seems to Wrap Up Inside the Hotel

Meals seem to be served in a restaurant themed on the galaxy. Dinner is Japanese cuisine from 18:00 to 19:30, and breakfast is Japanese or Western from 7:30 to 9:00 (year-round). The head chef is introduced as Mr. Ito.

Another thing that caught my attention was the “Ancient Garage.” Apparently it's a place where you can enjoy drinks, cigars, and pipes while looking at classic cars. It's open from 15:00 to 22:00, and the hours may change depending on the season. There also seems to be a guided stargazing program, but I couldn't find the times or the price.

Even without going outside, it sounds like you'd get the full set: bath, meals, garage, and starry sky. As an indoor person, that really piqued my interest.

Access for People Without a Car, and Notices Worth Checking Beforehand

On the access page, there's a note saying the hotel covers the taxi fare from Karuizawa Station to the hotel. It looks like you pay first and then hand in the receipt at check-in. However, the conditions for this weren't written anywhere. I also couldn't find any mention of a shuttle bus.

By car, the hotel is apparently along the Shiraito Highland Way. The access page says that if you tell the toll booth you're staying at the hotel, you don't have to pay the toll. On the other hand, a notice on the top page says that starting January 1, 2027, guests will also have to pay the toll (500 yen for kei and standard cars, once per stay). Since the handling seems to change depending on the time, it's probably a good idea to check the latest information before you go.

The top page also has a notice that Karuizawa's accommodation tax will be levied starting June 1, 2026. I also couldn't confirm the number of parking spaces, the parking fee, the distance or travel time from Karuizawa Station, or whether pets are allowed, on the official site.

Rakuten Mobile Signal Conditions

I entered the hotel's location (Karuizawa) into Rakuten Mobile's official coverage checker, “my Area Connectivity Simulation.” But no result appeared, and the screen switched to a message along the lines of “Currently under temporary maintenance.”

So the overall signal verdict came out as unknown. I had nothing to say it would connect well or poorly, so I'm just filing it under unknown here. The access page on the official site mentions that, because the hotel is inside a national park, calls may not go through on some devices, but I didn't see anything about Rakuten Mobile specifically.

If signal matters to you, it seems safest to check with Rakuten Mobile's official tool yourself as well.

Komorin

It was a little disappointing that no result came up. Apparently it's inside a national park, so I think it'd be a good idea to try the tool again before the stay.

See Rakuten Mobile Details

Wrapping Up

To sum it up, my impression of Ancient Hotel Asama Karuizawa is that it's a hotel with just 13 rooms in a small space that values slow time inside, with a large bath built from “crystal stones” and a garage where you can look at classic cars.

On the other hand, I couldn't confirm things like the check-in time, room rates, the spring quality of the large bath, or parking details from the official site. If you're thinking about staying, it seems best to check the latest information on the official site or the booking page. As for Rakuten Mobile signal, the official tool didn't give a result, so it's unknown. If you're curious, I'd recommend checking with the official tool yourself.

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