Myeonyeok Gongbang Royal Sauna Yeouido

Summarised from publicly available information — a 24-hour sauna on the first basement floor of the Hongwoo Building next to Lotte Castle Ivy, about a five-minute walk from Exit 2 of Saetgang Station in Yeouido. It is the Yeouido branch of the Myeonyeok Gongbang chain, and alongside the usual baths and sauna it runs a "myeonyeok gongbang" room where you sweat slowly at a low temperature on beds laid with wave stone. The sauna alone is 12,000 won, 25,000 won with the wave-stone room, and 8,000 won for children. Passes are sold too: ten plus two wave-stone sessions for 250,000 won, twenty plus three sauna visits for 240,000 won. It is open around the clock every day, but according to visitor reviews the wave-stone room does not operate at night, and the sleeping room is a small space with a few bunk beds, so it is not the sprawling 24-hour jjimjilbang some people picture. Body scrubs and massages are charged separately, and the owner notes in replies that foreign visitors often come for the scrub. Reviews mention alkaline water in the baths, and there is a request not to use phones inside the wave-stone room. Parking and wi-fi are available, groups are accepted, and the entrance is wheelchair accessible.