Osaek Tansan Oncheon is a carbonated and alkaline hot spring facility on the second basement level of the Osaek Greenyard Hotel in Osaek-ri, Seomyeon, Yangyang. The carbonated spring water is drawn from 470 meters underground and contains 1,090 PPM of carbon dioxide, and visitors use both the carbonated bath and the alkaline bath. It opened in 1993 and offers hot spring bathing at 650 meters above sea level in the southern section of Seoraksan National Park. After remodeling, the jjimjilbang is divided into various themes and temperatures, and the space is large and clean.