Literature has demonstrated the benefits of role-play simulations (RPS) for decision-making and social learning in the field of climate change and environmental policy. Despite growing interest, step-by-step guidelines are still rare when it comes to the practical design and implementation of RPS, which hinders the adoption and implementation of this promising approach. This article aims to facilitate the development of RPS by proposing a step-by-step framework for designing role-play simulations around three stages – before, during, and after the simulation. To develop the methodology, we use as a starting point a pilot simulation on decision-making and knowledge production in contexts of uncertainty and complexity. Focusing on negative emission technologies in Switzerland, the pilot simulation involved 12 scientists and 12 politicians who role-played each other for half a day. Overall, we propose an actionable framework for RPS designed to facilitate cooperation between groups with different socialisations, timelines, and imperatives towards more informed and collaborative decision-making practices. Doing so, this article contributes to making RPS more accessible to a broad audience as a method supporting cooperation between science and policy in the field of climate and environmental politics and beyond.