In this article, I examine Latin American regionalism from the collapse of the Free Trade Area of the Americas (FTAA) to the emergence and development of the Pacific Alliance (PA) in the period 2005 to 2015. For most of the research, I use the main economic blocs in the region, Mercosur as well as the PA, as the units of analysis. The main findings are that since the FTAA’s collapse, integration processes have become more heterogeneous; that Mercosur and the PA contrast with one another in political-economic terms; that the Brazilian project of establishing a post-liberal/post-hegemonic regionalism in South America has not succeeded; and that regional demand for Brazilian products is at risk of shifting to other markets in the medium to long term, thus further undermining its aspirations towards regional leadership. All of this is evidence of a decentred economic regionalism – that is, a form of regionalism in which no single state is in central command, or has enough followers to assume leadership and establish a dominant conception of integration and regional cooperation. Other factors contributing to this decentralisation are the poor economic performance of Brazil and Mexico, and the US government’s changed attitude towards trade relations with Latin America. Despite this, I argue that Latin American countries do need to strengthen cooperation within and among these regional blocs, aimed at promoting their joint global competitiveness. This will require cooperation rather than coercion, and networks and connectivity rather than hierarchies.