The practice turn provides new avenues for core questions of international relations and European Studies. This article draws on a practice theoretical account to shed new light on the constitution of agency in global politics. An understanding of agency as achievement that requires significant practical work and the participation in international fields of practice is developed. Drawing on the case of the field of counter-piracy practice and the European Union’s (EU’s) work to counter piracy off the coast of Somalia, it is shown how the EU achieved the position as a core actor in the field. A detailed discussion of the EU’s work in interrupting and knowing piracy, in building capacity, and in governing piracy is provided.