Let’s deal with the question first, because everybody has it and nobody wants to ask it out loud.
Yes, it’s naked. Everyone in the room, men and women together, no separate hours. Swimwear is banned outright in most German saunas. The reason given is hygiene: synthetic fabric holds sweat and chlorine and hands both back to a shared room.
Here’s the part the guidebooks get wrong. This is no ancient Germanic custom.
Into the early 1970s most German sauna houses still kept men and women apart, either in twin facilities or by alternating hours. In 1973 the German Sauna Association polled its guests and found a narrow majority, 52.6 percent, in favor of bathing together. What looks like a thousand-year tradition is about fifty years old.
The Rules, in the Order You’ll Need Them
Shower first. Then dry off properly, which is the step visitors skip. Dry skin starts sweating sooner.
Leave jewelry in the locker. Metal heats up fast in there.
Bring two large towels. One goes under you, and it has to go under all of you, feet included. No sweat touches the wood. That’s the rule Germans actually watch, and if you get it wrong, somebody will let you know. Politely, and right away. :-)
A round runs eight to fifteen minutes, usually somewhere between 60 and 90 °C (140 to 194 °F). The higher the bench, the hotter it gets. Start low.
Coming out, cool down in stages. Fresh air first, then cold water. Then rest for at least as long as you sat in the heat, which is the part that makes the whole thing work.
Two or three rounds makes a session. Stop there.
And it’s quiet inside. Phones stay in the locker, conversation stays low, and heavy perfume is about as welcome as a ringing phone.
The Aufguss Is Not Finnish
Every hour or so a Saunameister comes in with a bucket and a ladle. Scented water goes over the hot stones. Then comes the towel, worked overhead to drive the steam around the room. That’s an Aufguss, and it’s the theatrical centerpiece of a German sauna visit.
It is also a German invention. In Finland the same act is called Löyly and it’s plain: water on stones, no oils, no towel work, no show. The scent and the choreography came later, and they came from here.
The etiquette is strict and short. Once the door shuts for an Aufguss, nobody enters and nobody leaves. Sit up instead of lying down, because that heat surge goes straight to your circulation. When it ends, head out and cool off.
And here’s something the guidebooks leave out entirely: you can skip the whole thing.
I’ll happily sit out twenty minutes at 90 °C (194 °F). An Aufguss, though, and I’m done for the afternoon. So I read the schedule posted at the door and go in between rounds. Nobody minds, the room is calmer, and you get the bench you want. Plenty of regulars do exactly the same.
If You’d Rather Keep Something On
Germany has answers for that, and they’re easy to find once you know the words.
A Textilsauna is what it sounds like: swimwear allowed. Larger complexes often run one alongside the traditional rooms, so a couple can split up and meet in the café afterward.
Many houses also set aside a Damentag, a women-only day, usually one per week. It shows up on the timetable, and the front desk will tell you which day it falls on.
Inside a mixed sauna you can also simply keep the towel wrapped around you. It’s a little less comfortable and nobody says a word about it.
Even the grandest one runs both ways. The Baden-Baden Friedrichsbad opened in 1877. It walks you through a fixed Roman-Irish circuit of seventeen stations, roughly three hours end to end. The last one is a rest under a dome in Italian High Renaissance style.
Five days a week it’s textile-free and mixed. Two days a week it runs with swimwear.
It’s part of the UNESCO listing that covers the town. It also stands on the remains of the Roman soldiers’ baths, which turned up when they dug the foundations.
How Big This Actually Is
Around 30 million people here go to a sauna with some regularity. Counting the rooms in hotels, sports clubs, and gyms, there are roughly 10,000 publicly accessible facilities. Another 1.3 million or so are built into private houses.
What people say they get from it varies. Better sleep, fewer colds over the winter, one hour where the phone can’t reach them. I will make no claims on the medicine.
What I will vouch for is the hour afterward. Robe on, tea in hand, no particular plan, and a strong sense that the rest of the day can wait. That’s the part people come back for. ;-)
For the towns built around all this, see resorts in Germany. If you want one address to start from, make it Baden-Baden.