The aim of this Project is to analyze how the Collaborative Economy (CE) might influence sustainability of tourism in Barcelona. Since The Olympic Games in 1992, Barcelona has become a leader in many aspects, but especially in the tourism sector. Nowadays the city is a highly popular tourism destination and the tourism industry has made a significant contribution to the economics of Barcelona with the creation of incomes, taxes, hard currency and jobs (Sirakaya, Jamal, & Choi, 2001). Despite the high success achieved by “model Barcelona” it is important to take into accouny some challenges faced by the city in terms of tourism, creating a need for alternative and more environmentally and host-friendly practices in development, planning, and policies (Saarinen, J. 2006). One example of this is CE, which, since 2011, has started to have an impact on the Catalan capital, and all indicators show that the peer to peer (P2P) sites are one of the technology trends that are already radically transforming tourism (Sunyer, 2014). Collaborative consumption was named one of TIME Magazine’s 10 ideas that will change the world. All we do, create and produce has an impact on the environment (tourism generates an impact as well as the CE) and measuring the impact of our actions helps us to know where to improve and develop better strategies. The questions now are: what is the real impact that these new systems have on the city? Do they contribute to the path of sustainable tourism? To answer these questions and form a point of departure for this study, I interviewed different stakeholders: twelve experts from CE and tourism in Barcelona and 49 students from UAB University under the Tourism Grade. Interviews made to experts were based on face to face meetings carried out in two parts; firstly semi-structured questions and secondly a survey based on an evaluation of a previously selected tourism system indicator. The survey consisted of the evaluation of the European Tourism Indicators System – ETIS for Sustainable Destinatios, where the interviewees had to evaluate the influence of CE through the validation of the 27 core indicators (deciding whether the indicator would increase, decrease or remain equal with the influence of CE). The interviews conducted with the forty-nine students were made online and based on the survey evaluation of ETIS (like with the experts). The results show that CE could generate a better distribution of income around the city and could support the process of decentralization of tourism activity in the city center. Furthermore, it could strengthen social relations between locals and visitors, and thereby improve the negative perception that mass tourism generates in some specific points like Ciutat Vella. According to the stakeholders interviewed, the influence of CE in Barcelona could ensure a higher rate of satisfaction among tourists and increase the number of strategic plans of the city in terms of sustainability. On the other hand, in is noteworthy to consider the negative effects that CE could generate; the more distribution the city has, the more social friction is generated and so more specific managing plans are needed. Furthermore, interviewees considered that the occupancy rate in commercial accommodation and direct tourism employment would decrease, which means less incomes from the “traditional” tourism enterprises.