The main research challenge of this paper is to gain a better understanding of collective action to preserve High Nature Value (HNV) farming in the specific setting of post-transitional EU Member States of Central and Eastern Europe, which we explore using Slovenia as a model country. We apply the Social-ecological Systems (SES) framework and combine participatory and action research in considering different options for stimulating collective action of local actors in three social-ecological systems in Slovenia. We describe the systems, focussing on first-tier variables, and provide a comparison of their characteristics influencing the readiness to engage in collective action. Characteristics of system actors had the greatest influence on outcomes, followed by the social, economic and political setting (macro issues) and governance arrangements. Strong leaders enjoying the community’s trust are needed; rules must be transparent and individuals must have a personal interest to engage in cooperation. In a post-transitional setting, overcoming the issue of lack of trust is a limiting factor when attempting to stimulate collective action.