Citizens' initiatives and NGOs often aim to green society. They do this at a local level, but often large-scale changes are also pursued, changes we can label “transitions” towards a more nature-friendly society. However, such transitions are not easy to achieve. By drawing up and reflecting on a Theory of Change (ToC), active citizens can develop goals, strategies and concrete activities to increase their potential impact. In this research, we have reconstructed the Theory of Change in two projects:“Beach Clean Ups”, which try to draw attention to plastic waste throughout the Netherlands, and call on the government and companies to take their responsibility, and “Tiny Forests”, where IVN and local residents and schools work together. While both projects engage in local activities, we see clear differences in their strategy of using local action to drive large-scale change.