Policy discourses are important platforms for political actors to express their preferences on certain issues and are usually linked to a specific policy subsystem. From a research perspective, they have the potential to indicate ideological coalitions, policy change and learning. Using discourse network analysis, we identify core policy actors, issues, and coalitions in Switzerland's climate policy discourse and investigate how they have evolved over the past 15 years. In line with the policy process literature, we expected to see more stability than change in the discourse linked to the mature climate policy subsystem. However, our results have shown that policy discourses are more volatile than policy subsystems, and that national and international policy developments are able to trigger change, particularly in terms of the configuration of actor coalitions and the issues discussed.