Since Pre-Islamic times people from South-East Arabia were known as navigators and settlers in the Indian Ocean rim. Written as well as archaeological sources prove Omani maritime activities in the Indian Ocean which connected Oman with the Ancient Oriental civilizations as well as with the Hindus valley civilization from the 3rd millennium BC onward. Written sources from the Roman period, in first place the “Periplus of the Eritrean Sea”, evidence Omani activities as far as India and beyond. In this paper we shall outline the cultural, material and historical relations between the Arabs of the Southeast Arabian coast with the East coast of Africa. These relations have shaped and affected both worlds by creating a unique civilization, that established itself along the coasts of the Red Sea and East Africa since many centuries ago. We shall follow the historic and cultural steps of Arabs sailors, traders and nomads from South Yemen (Aden and Hadramawt) and South Eastern Arabia (Oman), which were the pioneers in the formation and development of this civilization over centuries. This cultural process lasted until the middle of the twentieth century and was stopped by the dramatic political events which coined the death sentence for the unique, multi-ethnic and multi-religious civilization. The article put the Arab and Omani heritage of the Swahili East African Coast within the frames of these historical events.