South Asia and Southeast Asia have been connected for centuries, with the degree of connectivity varying over time. This chapter explores strengthening connectivity between the two subregions by identifying the missing road and rail transport links, and analyzes the role of cross-border transport infrastructure investments. It assesses possible road and rail land corridors that would help create seamless transport connectivity between the two regions. Missing gaps and corresponding transport infrastructure projects are identified, and projects are screened and prioritized. For the selected critical projects, the study recommends a phased investment approach.