Since the UN Decade of Education for Sustainable Development (ESD), far-reaching efforts have been made to implement ESD worldwide. While ESD seems increasingly to be diffused as a social innovation related to environmental education, we still know little about how the concept is implemented through social relations and what role trust plays in this process. This article applies descriptive and inferential techniques of social network analysis to study how ESD is realised through social relations in Germany and the role of trust in this context. It is assumed that innovations such as ESD, which have been launched at the global level, are employed and diffused through communication exchanges at the regional level. Empirical results from this study show that the realisation of ESD is concentrated on the regional level, demonstrating social relations with high density within the regions and a lack of links beyond regional borders. Furthermore, the links of actors involved in implementing ESD tend to be concentrated on actors from the same sector. Explanations for this can be found in conceptual differences between ESD and environmental education, which have resulted in a serious void between political decisions, educational plans and the practical implementation of ESD.