OK, technically it's not a beach perhaps in that it is freshwater and not the sea, but I had a bit of spare time yesterday so took the time to visit one of Munich's public lakes, clearly advertised on the main Munich City web site as having a naturist area.

The lake is called Feldmochering See and it's only 30 minutes from the airport just a few minutes off the Autobahn.  And what's not to like? 

The naturist area is large, well attended, just a short walk from the car park (2 euros fixed fee, so cheap) and with concrete steps down into the lake, which has wonderful cool, crystal clear, water.  The area has something for everyone.  for the bold it starts at the footpath, for the less bold some parts are surrounded by trees and there is a large bank at one point, the bottom of which, right next to the lake, is largely out of sight, except to those already on in the naturist part.  There is, being Germany, a variety of ages, young families, some fairly pale, others "Mahogony"and every shade in between.

I would recommend it to anyone in the area with a bit of time on a nice day.