Local participation of stakeholders in governance of protected areas is considered to be important to natural resource management and biodiversity conservation. Social network analysis (SNA) is a useful tool for analysis because it allows the understanding of stakeholders’ relationships, interactions, and influences through communication networks. We combine quantitative and qualitative data to undertake a SNA for the natural park of Sant Llorenç del Munt in Catalonia, Spain. This is aimed at (1) assessing the structure of the communication network; (2) comparing the informal communication network with the formal participatory bodies of the natural park; and (3) selecting participants for subsequent analyses of the adequate governance structure of the natural park. The results suggest that an informal network of communication, which is reasonably well represented in participatory bodies, exists. However, this communication network is not functioning perfectly because stakeholders experience a lack of trust in the governance bodies of the park, which they perceive to be ineffective. Our results show that SNA is an effective tool to support the creation of a broad representation of stakeholders in participatory processes.