Located close to the heart of the Mombetsu downtown area (also sometimes written as Monbetsu) is the Mombetsu Central Hotel. It's a convenient spot to base yourself if you're visiting the region for the famous drift ice that forms off the coast in the winter months, as it's a short taxi ride to the departure point for the drift ice cruise tours.
Whilst the accommodations are fairly simple, my room was exceptionally clean, and I felt like it was more spacious than other accommodation spots I've stayed in across Japan. If you enjoy a soak in an onsen - and who doesn't during the winter months - you'll find one on-site, along with a sauna. There's also a restaurant at the hotel which serves breakfast and dinner, and we had breakfast included with our room rate. There was a bit of everything on offer, including fresh fruits, toast, granola, and lots of seafood including scallops and salmon. If you'd prefer to grab something yourself, there are a few restaurants within walking distance, and a SeicoMart (a Hokkaido-based convenience store chain) just a minute away on foot.
Like most hotels in Japan, there are free toiletries in the room - it helps to know this in advance if you're trying to travel light, but there was shampoo, conditioner, body wash, toothbrushes, razors, and hair brushes. The WiFi worked well in my room and in the lobby areas, so if you're in the area for work you shouldn't have any issues connecting.
If you're in the area for an extended period of time and need to do laundry, there's a coin-operated facility at the hotel. The hotel is also part of the current Go-To Travel initiative which helps to subsidize the cost of accommodation.