International tourism is increasingly viewed as one of the best opportunities for a sustainable economic and social development of developing countries. There is also an increasing concern from public policy makers as to whether mass tourism coastal resorts can play a catalytic role in the overall economic development and improve the real income of their community. In this paper, we present a general equilibrium model which explicitly takes into consideration specific features of some developing countries (e.g. coastal tourism, dual labour market, unemployment, migrations, competition between agriculture and tourism for land) to analyse the ways by which an inbound tourism boom affects this kind of country, in particular its real income. We define the conditions under which an inbound tourism boom makes developing countries residents worse off.