Flooding is a common experience in monsoonal regions of South East Asia, where diverse flood regimes have for centuries shaped agrarian and fisheries-based livelihoods. In this policy brief, we respond to the need for a nuanced understanding of the connections between flooding and migration in Southeast Asia. The policy brief summarizes key insights from a research project with eight empirical case studies in urban and rural areas across Southeast Asia. The policy brief outlines the multi-dimensional relationship between migration, vulnerability, resilience and social justice in Southeast Asia, cutting across the local, national and regional level, and offers recommendations on how to sensitize flood hazard policy agendas to the complexities of migration and mobility.