Differentiation has become a core feature not only in the European integration process but also in the implementation of European policies. Among the means to address differentiated implementation are European Administrative Networks (EANs). Through the exchange of information, best practices and advice, EANs are expected to contribute to more uniform implementation. However, the ways and extent to which they do so remain largely unexplored. This article addresses this gap through the empirical analysis of the European Network of Heads of Environmental Protection Agencies (EPA Network), drawing on a unique survey dataset and social network analysis. On the one hand, the findings uncover the EPA Network as a voluntary and informal network with a fragmented and clustered structure around key members. At the same time, several participants have recognised the network as a valuable asset to improving national implementation and developing innovative policy initiatives. Therefore, while there is significant diversity within and across the network, the network’s perceived contributions and added value point to the considerable importance of these instruments in EU policy implementation.