This cluster of floating wooden sauna boats sits at the far end of the Aker Brygge promenade, about 5 minutes from the City Hall. Same setup as the Langkaia location: wood-fired saunas heated to 80-90°C, jump in the fjord to cool off, repeat until your session ends. The boats use birch-burning stoves that crackle and smell like camping. You feed the fire yourself and pour water on rocks to create steam.
The view faces Akershus Fortress and the inner Oslofjord islands. You're moored right next to the busy Aker Brygge boardwalk where tourists eat ice cream and couples stroll at sunset. This means you feel more "on display" when you climb out of the sauna and jump into the water. People will watch. Some will take photos of the general scene.
Here's what they don't advertise: there are no showers on the jetty at Aker Brygge (but there is a hose you can use if temperatures are above freezing). Langkaia has a cold water rinse. This location doesn't. There are also no toilets on the boats or jetty. You must use public restrooms in the nearby shopping mall or restaurants before your session starts, or relieve yourself in the sea.
Prices at 250-300 NOK per person for shared sessions (FellesKOK), 1,400-1,600 NOK for private boat rental (PrivatKOK, up to 10 people). KOK Cruise around 4,000 NOK. Book ahead or you won't get in.