This study explores how bureaucratic structures shape shifting migration policy paradigms in Colombia and Ecuador during the Venezuelan forced displacement. Despite an underdeveloped legal framework, Colombia adopted a welcoming policy, granting Venezuelans a 10-year stay permit, driven by its operational migration bureaucracy Colombia Migration and the newly established Border Management Office. Conversely, Ecuador enforced restrictive measures influenced by its Ministry of the Interior, in spite of enshrining the right to human mobility in its constitution. Analyzing thirty-four interviews with key policy-makers, we reveal that the Venezuelan forced displacement led to a reallocation of migration responsibilities within bureaucracies, shifting migration policy paradigms. Our findings highlight the influence of bureaucratic structures—including institutional culture, mission, hierarchy, and specialization—on dominant migration policy paradigms. In doing that, this research bridges the literature on migration governance paradigms and national bureaucracies and challenges assumptions about the weakness of Southern bureaucracies.