Over half of the international migrants in the world migrate from one country in the global south to another, and the great majority of them cross a contiguous border. The predominant theoretical frameworks used to explain international migration dynamics stem from south-north migration studies and fail to fully address migration occurring in the global south. This dissertation explores the case of Nicaraguan migration into Costa Rica's export agriculture sector and how neoliberal economic policies affect the lived experiences of agrarian people. Using in-depth interviews, participant observation, and community surveys in the home and destination countries, it privileges the perspective of the migrant worker to understand migration initiation, integration, work, and the implications of migration for the families back home in a context of structural transformation.

South-south migration dynamics are shown to be distinct from the explanatory frameworks born out of the south-north migration literature. This is due to differences in relevance about assumptions about structural stability and the formation and maintenance of protective institutions for migrants. In the case of south-south migrations, a relatively rapid structural transformation is the essence of economic development and rational-choice indicators, such as the size of earnings and remittances, become less illuminating.

A social network approach is used to study migration of Nicaraguans into Costa Rica's rapidly expanding export agriculture sector in the context of neoliberal reform. This analysis focuses on migrant relationships, why they operate as they do, and how they change over time, and with what consequences. Migrants' vulnerability has led to the formation of relationships that diminish risk for the migrants, but not necessarily for families. These relationships differ by gender and the opportunities that individuals have in the both the sending and destination countries. The chapters in this dissertation follow Nicaraguan migrants working in the agriculture sector in Costa Rica while embedding their movements in shared southern context of neoliberal reform in the agriculture sector.