The tropical seaweed flora of Inhaca Island, Mozambique is compared to other areas on the east coast of southern Africa. A significant number of common taxa are recorded to occur between the tropical east coast of Africa and the Caribbean. Multivariate analysis reveals that the relationship between Inhaca Island and the Caribbean is stronger than with less distant regions, such as the warm temperate South African west coast or the tropical west coast of Africa. The phytogeographic links of these localities are discussed in relation to palaeoceanographic events.