Most of the Swahili port cities that occupied the western rim of the medieval Indian Ocean long-distance trading system were founded on islands. Dating from as early as the 10th century CE, Lamu and Zanzibar have become ' museumified ' as World Heritage sites, while other island port cities, such as Kilwa and Pate, are now uninhabited ruins. Mombasa Island, however, despite numerous calamities, is an increasingly important commercial hub and gateway into East Africa. This study aims to determine how some intrinsic benefits of islandness have shaped the settlement patterns and architectural forms that embody this continuous process of urbanisation. A typological analysis serves to explore Mombasa Island ' s layers of spatiality and morphology. More than any other East African city, this island reflects the synthesis of the distinctive settlement traditions of the Swahilis, Portuguese, Omanis and, subsequently, the British colonisers, through to its current state as a dynamic, modern urban centre. Compact, complex, and culturally diverse, its unique island concepts offer a wide range of contemporary urban and architectural solutions.