How does the European Union promote security beyond its borders? This article answers this seemingly straightforward question by exploring how the EU works as security community-building institution vis-a-vis non-members. Drawing upon practice theory in International Relations, the article unpacks the security community concept, focusing especially on the relation between co-operative security practices and the expansion of security communities. The article discusses how recent practice-inspired insights can be applied in empirical research to generate novel and interesting results of relevance for EU studies. It does so by recapitulating the main findings from a study on Spanish-Moroccan co-operation on civilian and military crisis management. The findings support the claim that common practice precedes collective identity in processes of security community-building in that the EU has helped bring together and perpetuate a community of security practitioners in the western Mediterranean that builds upon, as well as transcends, already existing bilateral relations.