Usually the tourism flows are explained by demand, economic growth, and revealed comparative advantage (neoclassic trade theory). This manuscript examines the link between intra-industry trade and international tourism flows. We have examined the Portuguese intra-industry trade in this sector. The analysis apply the static (Grubel and Lloyd) and dynamic index (Brülhart). Our results show that the tourism services are important for a small economy such as Portugal. The intra-industry trade is very significant between Portugal and the following countries: Spain, USA, Italy, Greece, Turkey and Canada.