Abstract This paper aims to examine the importance of co-operation for maritime security in the South Atlantic, focusing on the relationship between the national and sub-regional institutions that have leveraged this process, especially those from Brazil. For this purpose, the diagnosis addresses the debates around the contemporary roles of the navy and the importance of international co-operation for its mission accomplishment, highlighting the tasks judged as subsidiary, among them being that of maritime traffic control. The alignment of these co-operative activities with foreign policy and national defence projects can be seen through the navy’s participation in multilateral co-operation projects involving South America, particularly the Co-ordination for the South Atlantic Maritime Area (CAMAS). The research detects the existence of a particular model of a community of security practice in which national and sub-regional institutions have been generating an important maritime co-operative system, which is more stable than in other areas of co-operation in the same region.