Since its introduction in 2008, the Covenant of Mayors (CoM) has helped municipalities meet EU Climate and Energy goals and thresholds through Sustainable Energy and Climate Action Planning (SECAP). The engagement of local communities holds particular significance for smaller municipalities, which can leverage collective strategies to mutually contribute to climate change mitigation efforts, thereby optimizing results. In the realm of communities, Renewable Energy Communities (REC) have emerged as a potential tool for SECAP implementation, but although they target common objectives and constitute subsequent steps of the same planning flow, their interaction is poor. This study aimed to investigate similar tools’ integration by focusing on administrative and technical boundaries whose overlaps often hinder their interoperability. To this aim, the Italian framework was chosen due to the representation of its signatories in the CoM. Municipalities that have undertaken actions related to RECs within their Joint SECAPs have been compared through an analysis of the CoM datasets. Finally, two Italian case studies were selected to evaluate the impact of different territorial and institutional configurations on these initiatives, aiming to face climate change and achieve a green transition. This helped the authors propose practical recommendations and policy implications concerning this kind of community-centred energy planning solution as outlined in the concluding section.