Hornstullsbastun is the City of Stockholm's own public sauna on the Södermalm waterfront at Bergsunds strand. One electric sauna holds 16 people, and bookable 90-minute sessions for men, women or mixed groups cost 150 SEK, reserved online up to 30 days ahead. Bathers cool off with outdoor showers, sauna buckets and a swim. Open daily 06:30–21:30; swimwear must be worn throughout the visit.