This chapter examines the interplay between mobility, development and long-term planning in the context of Southeast Asia. At the intersection of geopolitical complexity and economic interdependence, Southeast Asia has experienced a remarkable degree of mobility, encompassing diverse areas such as rural–urban migration and transnational labour movements. The chapter examines the diverse impacts of these mobility patterns on the region’s development trajectories. The chapter also looks at the symbiotic relationship between mobility and development in Southeast Asia. It examines the convergence of migration dynamics, infrastructure initiatives and economic strategies and emphasises their joint influence in shaping the socio-economic fabric of the region. The chapter critically assesses the challenges and prospects related to long-term planning in Southeast Asia. It addresses the trade-off between short-term economic imperatives and long-term sustainable development goals.