A paradox of officially rejecting but covertly accepting irregular migrants has long been identified in the immigration policies of Western immigrant receiving states. In South America, on the other hand, a liberal discourse of universally welcoming all immigrants, irrespective of their origin and migratory status, has replaced the formally restrictive, securitized and not seldomly ethnically selective immigration rhetoric. This discursive liberalization has found partial translation into immigration laws and policies, but contrary to the universality of rights claimed in their discourses, governments reject recently increasing irregular south-south migration from Africa, Asia, and the Caribbean to varying degrees. This paper applies a mixed methodological approach of discourse and legal analysis and process tracing to explore in how far recent immigration policies in South America constitute a liberal turn, or rather a reverse immigration policy paradox of officially welcoming but covertly rejecting irregular migrants. Based on the comparative analysis of Argentina, Brazil and Ecuador, the study identifies and explains South American "populist liberalism" in the sphere of migration. We highlight important implications for migration theory, thereby opening up new avenues of research on immigration policy making outside Western liberal democracies, and particularly in predominantly migrant sending countries.