The Algarve region in Portugal is often considered as one of the most appealing regions for tourism in the country. Its attractive location and moderate climate have since the mid-1960s brought increasing economic prosperity. As a result of the development of mass tourism, available land-use resources were widely exploited to create an integrated tourist industry. In this area, economic prosperity has led to an increasing population and a significant growth of infrastructures to cope with the demand from the hospitality sector. The far-reaching land-use changes have, however, led to high pressures on the coastal areas of the Algarve. This region has shown an increasing loss of ecosystems resulting from the expansion of urban areas. This paper proposes a dynamic assessment of urban growth in the Algarve based on non-linear complex system modelling by using cellular automata converging on qualitative story lines with quantitative spatial methodologies. This new methodology utilizes both quantitative and qualitative spatial results by a comparative validation of built scenarios, in order to highlight future land use trends. In particular, three scenarios will be explored, each with distinct specific socio-economic paths. Our analysis to identify the scenario with the best fit, based on the evolution of the actual 2006 land cover, enabled us to build a future urban growth model for 2020 which was quantitatively assessed. The outcome suggests a picture of continuing growth for the region of the Algarve within the framework of current policies and regressive spatial trends. © 2011 Elsevier B.V.