Hisøy Badstueforening

Hisøy Badstueforening runs a floating, wood-fired sauna at Sagholmen in Galtesund outside Arendal – on an uninhabited islet that can only be reached by boat.

The offering is membership-based: shared sessions run on Fridays with room for ten people, and the rest of the week members can book private three-hour sessions. A changing room is in place, and you take your saltwater dip right from the sauna.

Booking is through the association's booking page. A unique little sauna adventure in Arendal's archipelago – membership is the key.