This study evaluates the carbon footprint (CF) of Barcelona tourist activity taking into account the above 30 million visitors who visit the city every year. This study analyzes the main sources of emissions considering direct (Scope 1) and indirect emissions (Scope 2 and 3) as a consequence of energy use. This research has been carried out in close collaboration with Barcelona City Council and in the context of the new Strategic Tourism Plan for Barcelona city. The impacts of arrival and departure transport, accommodation, leisure and professional activities and Intra-urban transport from Barcelona city were all included. The total CF of Barcelona tourist activity is about 9.6MtCO(2) eq/year, which represents an emission of 96.9 kg CO(2)eq/visitor day. The main source of emissions is arrival and departure transport (95.6%), and particularly aviation. These results show that if substantial reductions in CO2 emissions are to be achieved, initiatives strategically focused on transport and also accommodation are necessary.