Sea trade in East Africa was generally conducted with those countries that lay across the Indian Ocean. In particular, there was a great deal of trade with China and with places like Persia and Indonesia.
The East African kingdoms had many things that were wanted in trade. These included ivory, gold, and rhinoceros horns. In return, the East Africans imported things such as iron goods, porcelain from China, glassware and cloth from India. There were also those who came from what is now Indonesia to trade spices like cinnamon. Some of these people are responsible for the fact that Madagascar has a mixed African and Malay population even today. They are also responsible for introducing such foods as bananas and yams to Africa.