Abstract: Over the past five years, the South Atlantic region has become a central element of Brazil-ian security policy, with Brazil actively supporting the notion of a trans-oceanic security conscious-ness involving African littoral states. It has invested in diplomatic initiatives such as the Zone of Peace and Cooperation of the South Atlantic (ZPCSA, or ZOPACAS), and extensive military co-op-eration with West African states such as Sao Tome e Principe, Namibia and Cape Verde. Its internal security and defence policy documents have repeatedly been updated to reflect this dimension, and now provide the foundation for advancing these initiatives. This policy thrust is directed at securing Brazil’s offshore oil assets, and limiting the influence of what it has termed ‘extra-regional powers’ such as the P-5. This article highlights these initiatives and reviews the prospects for this policy by examining the plausibility of the South Atlantic region as a regional security complex in the sense coined by Buzan and Waever. The analysis is based on the role of geographical and linguistic proxim-ity in international relations, and the impact of multilateral bodies on building support for a regional approach to security governance.