Dogs are generally required to be on a leash throughout Germany's national parks, a stricter baseline than the general countryside rule covered in the previous article, since national parks protect especially sensitive habitats. Berchtesgaden National Park's own visitor rules state dogs must be leashed, alongside staying on marked trails and leaving wildlife undisturbed, enforced by rangers year-round. The Bayerischer Wald National Park similarly bans letting dogs run free, even in a state like Bavaria that otherwise has no blanket forest leash law.

The Wadden Sea National Park (Nationalpark Wattenmeer), spanning the North Sea coast of Schleswig-Holstein, Lower Saxony and Hamburg, applies a notably specific and strict rule: official guidance for the Schleswig-Holstein section states dogs must be leashed at all times, year-round, on all dikes and foreshore areas and throughout the park itself, under both the state water law and the national park law. Unlike most leash rules in this guide, the reasoning here is only partly about wildlife — grazing sheep on the dikes help compact the soil and keep it storm-flood resistant, and a dog digging or chasing sheep can damage the dike's structure directly, alongside disturbing ground-nesting birds.

Consequences for an off-lead dog in the Wadden Sea park are correspondingly serious: a violation can be treated as an administrative offence under the water or national park law, and if a dog injures or kills a protected bird or destroys its eggs, the owner can face criminal liability under Germany's federal nature conservation law (Bundesnaturschutzgesetz). It's a genuinely stricter standard than a typical 'keep dogs on leads' sign, and worth building a North Sea trip's walking plan around from the outset rather than discovering it at the dike itself.