This chapter examines the challenges of governing cross-border data flows within a fragmented global legal landscape with a focus on the tension between digital sovereignty and transnational data mobility. It argues that legal fragmentation is a structural feature of contemporary data governance, producing regulatory conflicts and reinforcing power asymmetries between states, corporations and individuals. The chapter analyses how state-led sovereignty strategies and societal as well as technological resistance seek to address these challenges but often reproduce underlying fragmentation. It then explores pathways toward more coherent governance through interoperability, institutional coordination and shared normative principles. In doing so, it highlights the importance of aligning global data governance with broader commitments to inclusive development, accountability and the values reflected in the sustainable development goals.