This chapter analyses the major shifting patterns of migration in East Africa over the 19th century and in the early 20th century. The analysis is structured around four historical processes that produced major shifts in migration patterns in East Africa: (1) the development of the plantations on the coast and in Zanzibar; (2) the expansion of ivory exports to global markets; (3) the growth of urban centers in relation to long-distance trade; (4) the establishment of European colonial rule. The chapter will discuss the rise, transformation, and decline of the migration systems that developed as a response to these historical processes. It will combine qualitative sources and the limited available quantitative evidence in order to investigate the major drivers of migratory change and to provide a degree of magnitude of the migration flows in East Africa in the 19th and early 20th century.