Germany's geography offers a genuinely wide range of swimming spots for a dog — Alpine lakes in Bavaria, the Mecklenburg Lake District's thousands of lakes, Rhine and Elbe riverbanks, and long stretches of North Sea and Baltic coastline. Away from designated, busier public swimming beaches, many lakeshores and quieter river stretches are informally treated as fine for a dog to swim, though a specific municipal beach may post its own signage restricting dogs during the busiest summer weeks, and the dike-specific leash rule on the North Sea coast, covered in the national parks article, applies regardless of whether a dog is swimming or walking.

The one genuine caution for a high-summer swim, the same hazard covered for Sweden's lakes elsewhere in this guide, is cyanobacteria (Blaualgen, blue-green algae) blooms, which occur in German lakes too, mainly in warm, still conditions in July and August. German consumer and veterinary guidance advises treating any visible green or blue-green film on the water as a reason to keep a dog out, since the toxin risk can't be judged by looking and symptoms like vomiting after swimming or fur-licking warrant an immediate vet visit.

Many German lakeside and riverside towns, particularly around the Bavarian Alpine lakes and the Baltic coast, have embraced designated Hundestrände (dog beaches) specifically, which is a genuinely easier option than guessing at an ordinary public beach's unwritten rules during peak season — worth a quick search for the specific lake or coastal town on the itinerary.