Kokuminshukusha Sanbeso is a public lodge situated at the southern foot of Mount Sanbe, approximately 450 meters above sea level, within the Sanbe Mountain National Park in Shigaku, Sanbe Town, Oda City, Shimane Prefecture. Sanbe Onsen is said to have been discovered during the Hakuho period (late 7th century), and by the Kansei era (1789-1800) it had become widely known as a therapeutic bathing destination. In 1959, it was designated a National Health Resort. The hot spring carries over 1,300 years of history, born from the volcanic activity of Mount Sanbe. In 2023, the facility gained national attention when it hosted a match of the prestigious Osho shogi tournament.

The water is classified as an iron (II, III)-containing sodium chloride spring with a mildly acidic pH of 5.9. The source temperature is approximately 34.8 degrees Celsius, with a generous flow rate of 1,174 liters per minute. The total output across all Sanbe Onsen sources reaches approximately 3,000 liters per minute, the largest in the Chugoku region. Due to its high iron content, the water is colorless and transparent when it first emerges but oxidizes upon contact with air, turning a distinctive tea-brown color. The water also contains sodium bicarbonate, offering skin-beautifying properties. All baths are free-flowing from the source without any dilution, recirculation, filtration, or disinfection, and some baths are offered without heating.

The highlight is the collection of 16 uniquely designed outdoor baths, including rock baths, sake barrel baths, iron cauldron baths, and bamboo boat baths. Indoor baths and a sauna are also available. Day-trip bathing costs 700 yen for adults and 400 yen for elementary school students, available from 10:30 to 21:00 (last entry 20:00). Overnight stays start from 14,300 yen per person with two meals. An on-site restaurant is open from 11:30 to 14:00. Free parking is available for 70 vehicles.