Climate assemblies have emerged as participatory mechanisms and as socio-educational spaces for engaging citizens in climate decision-making and promoting sustainability learning. However, to date, initiatives involving children and young people remain underexplored. This study investigates the implementation of climate assemblies involving children and youth in the United Kingdom, focusing on the perceived success factors and conditions that enable meaningful participation and learning, as well as the challenges and opportunities that emerge when developing deliberative democratic processes with younger participants.