Lynx, wolves and brown bears are returning to areas in Western Europe from which they have long been absent. This raises specific questions, not only concerning the effective conservation of transboundary carnivore populations, but also regarding potential consequences for livestock, hunting, human safety and the like. Intense popular debates tend to ensue wherever large predators reappear. The response by public authorities, however, must respect the limits imposed by international and European nature conservation obligations. This article is intended to bring these limits into focus by introducing and analyzing relevant species protection regimes, chiefly the Bern Convention and the European Union’s Habitats Directive. Legal issues are addressed regarding conservation status, prohibitions, derogations and transboundary management plans. Also addressed is the interesting predicament of ‘frontier states’ like the Netherlands, which seem to provide the ultimate test case for the adaptive capacity of carnivores and conservation law alike.