Research on migrant youth's school transitions has focused on the country of residence, ignoring migrant youth's pre-migration lives in the country of origin. Drawing on 14 months of multi-sited ethnographic fieldwork between Ghana and Germany, this paper instead analyses school transitions through migrant youth's mobility trajectories, encompassing all geographic moves and concurrent family constellations over time and space, both before and after migration. A mobility lens shows how resources gained in the country of origin -- including confidence, discipline, respect, and adaptability -- help migrant youth navigate their school transitions in the country of residence, thus becoming forms of transnational cultural capital.