Security networks are increasing in number and in importance across the security field as a means of providing inter-agency coordination. On the basis of a detailed qualitative study of networks in the field of national security in Australia, this article aims to advance our knowledge of the internal properties of security networks and conditions shaping their performance. It places ‘cooperation’, ‘coordination’ and ‘collaboration’ on a continuum, with cooperation at one end and collaboration at the other end, and aims to illustrate how each of these ‘Cs’ shape the performance of security networks. The central argument is that the performance of security networks increases as the network moves from cooperation to collaboration. Drawing on interviews with senior members of security, law enforcement and intelligence agencies, the article aims to highlight the lessons for how to strategically manage security networks in ways that promote collaboration.