Abstract <p>Participation in multilateral negotiations such as those on climate change is key to understanding negotiation processes and outcomes. Despite its importance, participation – what negotiators actually do – remains understudied and ill understood. We address this gap by examining participation in UN climate negotiations. Specifically, we collect data across all 198 Parties and 58 negotiation sessions (subsidiary body meetings, SBs, and Conferences of the Parties, COPs) since 1995 on a total of six activities across both negotiation and non-negotiation spaces: oral interventions, written submissions, and services as chairs for negotiation activities; and press conferences, side events, and exhibits for non-negotiation spaces. Our analysis shows that participation spans different spaces, even if negotiations dominate. Nevertheless, non-negotiation spaces are growing in importance, with COP15 serving as a turning point. Non-negotiation spaces complement negotiations: Parties active in negotiations also tend to pursue non-negotiation spaces. Finally, Parties differ strongly in the extent to which they engage, with many Parties remaining relatively passive, sometimes despite a continuous presence at negotiation sessions. These observations already help to understand UN climate negotiations better, but invite further work, including more qualitative research – for which our data can provide a helpful starting point.</p>