Adam
Google
We didn’t stay at the hotel, but dropped in to visit the hot spring after camping elsewhere. Prices are very reasonable (¥700 for adults, ¥500 for kids), and the process of buying tickets is smooth enough using the ticket machines next to the counter - a bit of a strange process as you immediately have to take your tickets to the counter anyway.
The hot spring itself is natural volcanic water, complete with sulphur making for an eggy odour and numerous health benefits. There are indoor and outdoor baths, outdoor ones being way more comfortable in the summer heat. None of them were too busy to be able to get in.