Full text can be accessed at http://www.sciencedirect.com/science/article/pii/S1874599797800135This chapter describes the coastal basins of Somalia, Kenya, and Tanzania. The western Indian Ocean seaboard is an Atlantic type of continental margin; hence, the sedimentary basins involved are typical pull-apart basins of Klemme. However, the margin has been subjected to transform movements through late Jurassic to late Cretaceous times when Madagascar was moving southward relative to Africa. The margin seems to have been an emergent and stable block during the whole of Palaeozoic time. Sedimentation starts on top of a peneplaned Precambrian basement surface made up of highly metamorphosed rocks. The first epeirogenic movement to affect the region formed a series of intersecting basins separated by structural highs. The latter include the Bur-Acaba uplift of southern Somalia and the Nogal and Hargesya-Ergavo uplifts of northern Somalia. The existence of thick Pre-Jurassic sediments in the axial part of Luug-Mandera Basin is indicated by the discrepancy between section inferred from geophysical data and those measured in the penetrated sections.