This article aims to present the evolution and further perspectives of the external action by the European Union Agency for Law Enforcement Training (CEPOL). By analysing the legal background in light of the subsequent mandates of the Agency and against various policy documents, the authors demonstrate the impressive evolution of the past 20 years, both in terms of volume and quality, that has made CEPOL a key player in the European Union’s internal-external security nexus. The Agency has managed to engage nearly all countries in the EU’s proximity on the one hand by concluding cooperation instruments, on the other hand by managing dedicated capacity-building projects. Via all these means, the European law enforcement culture is spread among partner countries’ law enforcement communities. CEPOL is thus actively contributing to the high level of internal security of the European Union, serving its primary customers, i.e. the EU Member States, and well beyond the borders of the Union.