Water resources have a fundamental value for both ecosystems and society. However, changes in climate, population, consumption patterns, land use and urbanization are affecting its quality and future availability. In Andorra, a country located in the middle of the Pyrenees, the confluence of climate change and a socioeconomic model with an important weight of tourism industry based on an intensive use of water could threaten the future sustainability of water resources. This paper analyses the water resources of Andorra and its future sustainability using the Water Evaluation And Planning system (WEAP) modelling tool. The WEAP-Andorra model presents an initial estimate of the national water demand segregated into the main water consumers of the country (tourism, residential, primary sector and power generation). It explores the future evolution of water resources combining climatic and socioeconomic scenarios such as evolution of the population, tourism, power generation plans and land use patterns. Results of scenarios show that in general terms and at country scale the impact of climate change will not compromise the future water demand. However, in some locations and in specific periods or seasons it could be some challenges to give response to all the demands and rise tensions about what water uses should be prioritized, especially between tourism and ski resort and resident uses. The WEAP model presented in this paper is demonstrated a useful tool to support management, decision-making and the design of policies for sustainable water management and adaptation to climate change.