Plötzensee

U7 U-bahn to Seestrasse, then the 23 or 24 tram west to its end station, then about a ten minute walk.

This idyllic little lakeside beach is hidden out towards the airport in Wedding, about 1/2 hour from Friedrichstrasse. It’s one of the swimming spots in Berlin that’s been privatized (so your regular Berlin Badebetrieb passes won’t work here), and with good results. The cost is the same as at the regular city pools (about 4 Euros in August 2002), and will all the usual amenities: grassy fields for grilling, dangerous-but-exciting-looking Spielplatz for the kids, pleasant FKK section with a pier to lay on, fully stocked snack bars at both ends of the beach, terrace restaurant, and more greasy salty food options than anyone needs at the beach.