This paper examines the often-overlooked role of delegation composition in climate negotiations under the UN Framework Convention on Climate Change (UNFCCC). While prior research has emphasized delegation size as an indicator of negotiation capacity, we argue that size alone fails to capture the complexity of national presence at these talks. Our extensive original database covers all individual participants in UN climate change negotiations, including all COPs and Bonn Subsidiary Meetings (SB). Our analysis covers 58 meetings between COP1 in 1995 and SB58 in 2024. The database allows us to trace participants over time and to identify their role in a country’s delegation. Based on this rich individual-level data, we create several dependent variables to create a holistic view of delegation composition, including the level of experience of the most senior negotiators, the share of external experts from NGOs and the private sector, the amount of government bureaucrats represented in the delegation, as well as the size of the supporting entourage. Theoretically, we build upon institutionalism, two-level games theory, and multi-level environmental governance to explain country delegations’ composition. Empirically, we use multilevel regression analysis of delegations clustered in countries and in years, with country-level and meeting-level covariates. Our paper shifts focus from delegation size to the qualitative aspects of participation in multilateral negotiations, offering a more nuanced understanding of countries' capacity to participate meaningfully in global climate policy.