["Global Networks, EarlyView. ", "\nAbstract\nMixed migration is an international regime in the making. The migration and refugee crisis put the topic high on the global agenda and multilateral initiatives like the Global Compacts for Migration and Refugees have started to address it. However, it is a contested policy issue and agreement on legally binding instruments is difficult to achieve. While formal global mixed migration governance is thus only emerging, in this article I argue that international organizations shape how mixed migration is governed through informal means. Mixed migration experts in intergovernmental organizations, regional agencies and non‐governmental organizations form networks that cut across organizational levels and boundaries to create practical knowledge and to train fieldworkers. Based on interviews and the analysis of training material, this article shows that they have considerable influence over policy implementation because they control the content of training tools and devise scripts for best practices that guide how mixed migration is governed on the ground.\n"]