The Universities’ Mission to Central Africa (UMCA) missionaries equated urbanity with moral contagion, to which those with slave status were especially vulnerable. To the ex-slaves who came into contact with the mission, the growing commercial centre of Zanzibar, and the coastal cultures it was associated with, were not only enticing, but crucial to social and economic mobility. The mission’s ex-slaves did not enjoy a special advantage though their connection to missionaries. Even for the missionaries’ most treasured dependents, the advantages were ambiguous. However, the mission did facilitate the making of strong cohorts and ease the transition to living in the town.