This hotel is a little tricky to get to, as you first have to get yourself to the Noboribetsu JR Station, then take a bus (approx. 45 min.) to the Noboribetsu Gateway Center Bus Station, then a short (<5 minute) walk across the street to the Noboribetsu Manseikaku hotel Onsen. By the way, if you buy your two-way bus ticket at the JR Station, it is slightly cheaper.
The check-in process can be a little tedious, as this hotel can be very strict with their check-in time, and in that you are given an escort to your room, who will provide a brief orientation and answer any questions.
The room we had, is not of a typical Japanese onsen style. We were fortunate to have a large queen size bed, with TV, fridge, etc.
As for the buffet dinner, not bad, I would not complain; with sushi, dumplings, pasta, noodles, steak, venison, etc. And the buffet breakfast - nothing special, typical Japanese Onsen Hotel style. One thing to remember is that alcoholic and soft drink beverages will incur an additional cost, though there is a free drink bar available with coffee, tea, water, and a small assortment of juices.
As for their facilities, they have two extremely large segregated public hot spring pools, indoor co-ed swimming and whirl pool.
And what to do in this area for excitement, there are many hiking trails with names like Hell Valley, that will easily take up most of your time and many photo ops especially during the month of October due to the changing of the leaves. Therefore a two night stay would be justifiable.
The one major issue I have, is that the public hot spring onsens are crowded during the day and evening. Best time to hit them is late in the evening, well after dinner, or after midnight - then you can have the spa almost all to yourself.
Be forewarned, that English is not widely spoken in these here parts, though you should be fine with the front desk. And no Tipping - fantastic. There is some shopping in the area that is geared primarily to the Japanese tourist.
To really have a leisurely time here, you need to spend at least two nights, if it is within your budget.

Would I recommend this establishment: Definitely

Would we return: Yes, though we would go for two nights, instead of one.

Good: Clean room, has indoor swimming pool, room rate is cheap

Drawback: No internet connection at all, no free bus service from JR Noboribetsu, slow email response and no correct answer obtained

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Room stayed: Single (western style)

This hotel is under the hotel chain Manseikaku. Expect to get great service but I feel disappointed. They have slow email response. Send email to ask if free bus pick up service provided, but they replied me that I sent the email to the wrong person. I suspect they have misunderstood my email which was writen in English.

I took Donan Bus in front of the JR station to this hotel. One way ticket cost 330 yen. I hope the hotel provide free bus to JR Noboribetsu, so I did not ask for return bus ticket. In the end, to my disappointment, no free bus service provided.

According to the donan bus website (in japanese), the return ticket sold at 600yen. Not very sure where to get it. Probably at the JR Noboribetsu station counter.

The hotel is opposite the Noboribetsu Onsen Bus Terminal. The building looked good. Lobby is spacious. Front desk staff can speak simple English. Not really a problem to communicate with them.

Due to the design of the building, my room is located quite far from the elevator. Can only see the inner hotel building from my room. The room is small, but nice and clean. Green tea pudding was served (put inside the fridge). Taste normal.

Universal plug adapter is provide in the room. This is the 1st hotel I stayed so far that provides universal plug adapter. But it is also the 1st hotel that doesn't provide internet connection at all.

Did not pay attention to the air condition in the room because it was snowing when I visited Noboribetsu. However, I did open the window when I was sleeping that night. So it may be quite stuffy as mentioned by traveller wyjc, especially during summer.

There is an indoor swimming pool (closed at night). Onsen opened for 24 hours. Indoor onsen has water jet bath and sauna (closed at night). Because the onsen is located at level 3, no nice view for the open air onsen. Personally prefer the indoor onsen.

Dinner and breakfast are in buffet style. Quite a good variety and taste is okay.

As a summary, paying 5925 yen (including 2 meals and onsen tax) to stay at this onsen hotel is considered quite cheap. But I may try other hotels in Noboribetsu for my next visit though.

First time to stay in a Ryokan style room. You sleep on the floor with a comforter and a beaded pillow. If you would like to experience this, you may want to try this hotel. The room feels a bit outdated. The aircon is controlled at 23-25 deg Celsius - can't make it any cooler. We stayed here for one night only. The onsen inside the hotel is nice. There is an indoor and outdoor onsen. I liked the outdoor better. Breakfast and dinner are buffet style with plenty of choices. 15 minutes walk to the Hell Valley. No free internet or free wi-fi in this hotel.