It is important to remember that while the SCP Foundation continues in the public, many of the specifics about the Foundation's activities are shrouded in secrecy. This is where the Department of External Affairs comes in to play. The DEA is responsible for planting disinformation about the activities and identities of Field Agents and (occasionally) Mobile Task Force Operatives. The Department of External Affairs is also responsible for plugging leaks about many of the specifics of the SCP Foundation. Secondarily, the Department of External Affairs manages external relations with anomalous and non-anomalous Groups of Interest and Organizations. The DEA also manages the release of information to the public.

Formerly, the Department of External Affairs was responsible for the recruitment of foundation Personnel from military and scientific institutions, the acquisition of D-Class Personnel, and concealing the existence of Foundation Secure Facilities from the public; however, since the knowledge of the anomalous became part of the public knowledge, these activities have either been halted or transferred to other internal departments.