A historic sauna is worth the trip on its own, for the building, the tradition, or both. Some have run continuously for a century; others are careful restorations of bath culture that nearly didn't make it. Either way the session carries a weight a new-build doesn't, and the löyly tends to be taken seriously.
In Germany, 7 of the curated saunas fit this cut. See the full Germany country guide for every venue, or keep scrolling for just the historic saunas.
Every historic sauna in Germany

Bartholomäus-Therme
€Hamburg, Germany
FinnishSteam

Hotel Badehaus Goor
€Putbus, Germany
FinnishSteam

Hotel Drei Quellen Therme
€€€Bad Griesbach i. Rottal, Germany
FinnishSteam

Kristall Kur- und Gradier-Therme Bad Wilsnack
€€Bad Wilsnack, Germany
FinnishSteam

Lützow Sauna
€€Berlin, Germany
FinnishSteam

Münster-Therme
€Düsseldorf, Germany
FinnishSteam

Stadtpark Sauna
€€Hannover, Germany
Finnish