As “learning places for sustainable development”, UNESCO biosphere reserves are specifically dedicated to sustainability. The Lima Action Plan of 2016 resolved to position the biosphere reserves more prominently as model regions in order to fulfill UN Sustainable Development Goals (SDGs). However, the question remains how and to what extent this resolution has been implemented and the ideal of sustainability filled with life at the local level. Based on surveys of municipal actors and fifteen in-depth interviews with political decision-makers, this article compares three adjacent Western European biosphere reserves, the Palatinate Forest, Northern Vosges, and Bliesgau, with regard to local initiatives aimed at fulfilling the overall task of sustainable development. The results show—besides generalized statements on the relevance of sustainability—that municipal politics is only, to a limited extent, guided by the requirements of concrete SDGs. Nevertheless, many of the measures implemented do ultimately reflect these goals. Along with specific ecological and climatic projects, these comprise future-oriented settlement policies and educational activities undertaken by the biosphere reserves and their municipalities. In this context, improved communication with local councils and residents might well lead to more effectively structured implementation of SDGs.