Abstract Background Local collaboration of community organisations and healthcare organisations is seen as relevant for the efficiency and efficacy of health and social care because of their potential role in providing social involvement which may reduce the need for the utilisation of formal services. Care organisations connect to each other in different ways, thus comprising an organisational network. This study aimed to describe and explore organisational networks with respect to their activities for people with diabetes mellitus type 2 and potential mechanisms of effective collaboration. Collaboration could include, for example, referring to each other and organising activities together. Potential mechanisms are navigation, negotiation and contagion. Methods A mixed methods study was conducted in an urban and a rural area in the Netherlands. The participating organisations were mentioned by a sample of diabetes patients in these regions and by organisations’ representatives in a snowballing procedure. Next a quantitative survey and a semi-structured interview were conducted, including 35 representatives of these local organisations. The social network analysis methods was used to map and characterise the organisational networks based on results from the survey. A thematic analysis of interviews was undertaken to identify how three mechanisms (navigation, negotiation and contagion) were used in the collaboration. Results Both interviews and network structures showed evidence of navigation-related mechanisms. Organisations referred patients with diabetes to services within their organisation or to relevant services provided by other organisations. Hardly any negotiation or contagion-related mechanisms were identified. If negotiation between organisations was found, it seemed externally enforced. The density, centrality, and reciprocity in the networks seemed low to facilitate contagion of practices. Some organisations reported actions that could have impacted on contagion. Representatives emphasized the need of network collaboration with local or regional community and healthcare organisations. Conclusion The study suggests that navigation to resources is a relevant theme in organisational networks, which could be targeted by interventions. More research is needed to explore the relevance of other network-related mechanisms.