Relatively little is known about the precise activities of the European External Action Service (EEAS) headquarters in the European Union’s (EU’s) international climate diplomacy, especially since the adoption of the Paris Agreement in 2015. This article therefore sketches the evolution of the climate diplomacy activities undertaken by EEAS headquarters between the 21st Conference of the Parties (COP21) in 2015 and COP26 in 2021. Based on a triangulation of official documents and twenty semi-structured interviews, the article finds that although the EEAS headquarters continues to coordinate and mainstream EU climate diplomacy, it has also become more outwardly-involved and entrepreneurial. This entrepreneurship can be explained by the creation within the EEAS of an Ambassador at Large for Climate Diplomacy, the working style of the appointed ambassador, increased resources at EEAS headquarters dedicated to climate diplomacy, and a favourable institutional context within the EU. These findings provide a detailed and updated insight into the involvement of EEAS headquarters within EU climate diplomacy. Accordingly, they improve our understanding of the EU as a climate actor and also demonstrate the importance of individuals in shaping how the EU conducts its climate diplomacy.