This article focuses on institutionalized forms of diplomatic cooperation among European Union (eu) members in southern Mediterranean capitals. It argues that European diplomatic cooperation represents a thin form of multilateralization of member states’ bilateral relations with southern Mediterranean countries. By analysing diplomatic presence on the ground, it shows that the European Union delegations in the area are not only big, but also politically strong, and they interact with a large number of national diplomats. The article examines how eu delegations in the southern Mediterranean represent a diplomatic ‘site’, in which diplomacy occurs in the shape of information-gathering, representation and negotiation, including among eu member states. This does not amount to a single European diplomatic system, however, as coordination remains thin to date and the agenda-setting mechanisms for eu delegations’ work and for European diplomatic cooperation have not (yet?) been fully developed.