Abstract The EU participates in many international fora related to climate change (for example UNFCCC, G20, Montreal Protocol), which collectively constitute the international regime complex on climate change (IRCCC). Using the case study of negotiations on the Paris Agreement, this paper addresses the question How and why did the EU use the different fora of the IRCCC to achieve its objectives in the Paris Agreement negotiations? It finds that the EU used the IRCCC in four main ways: employing typical multilateral negotiating activities, overcoming specific issues of the Paris Agreement negotiations, creating political momentum, and ensuring cross‐fora coordination. These uses correspond with the level of political authority of participants and the level of climate‐specialization in a given forum.