Migration from Yemen to East Africa has been occurring for centuries and continued well into the twentieth century. Since the European explorations of the nineteenth century the term 'Arab-Swahili', as distinguished from 'African', has been in use. The ways that Yemenis have both adopted and changed Swahili culture in Kenya are outlined in this paper. Most Yemeni migrants who settled in Uganda passed through Mombasa, acquiring some knowledge of the Swahili language en route. However, the Yemenis of Uganda are not Swahili, despite using the Swahili language as a major medium of communication, even at home. Ugandan 'Arab' food eaten at home and cooked by Yemenis in cafes is actually Indian/Swahili cuisine. The ways that Yemenis have promoted the cultivation of qat across Uganda and have made its consumption a marker of identity are described. The degree that the terminology of diaspora studies can be applied to Yemenis in Kenya and Uganda is assessed, and concludes that the migrants are both 'cultural hybrids' and 'transnationals'.