Tourism induces migration for economic and social reasons, a process leading to socio-cultural, economic and ecological change. Tourism infrastructure development often attracts migrants over long distances, particularly in developing countries where tourist numbers have increased rapidly in recent years and where relative and absolute poverty in economic terms is a widespread phenomenon. In order to analyse the scale and importance of such tourism-related migration, a survey was carried out in Zanzibar, Tanzania. The results indicate that the migrants shape the characteristics of the tourist industry in Zanzibar and that their presence has a considerable impact on the island's culture, economy and environment.