Competition law versus spatial planning in vacation rentals in Spain 1 Joana M. Socías Camacho Associate Professor of Administrative Law University of the Balearic Islands I. INTRODUCTION Collaborative tourism, with its spatial and urban-environmental impacts on the one hand and the principles of freedom of enterprise, open competition and the guarantee of market unity on the other, represents an economic activity that cannot be excluded from regulations. The boom of the so-called collaborative or sharing economy has clearly changed the shape of two very important sectors: transport (with the appearance of Uber and Cabify) and tourism (with the emergence of collaborative accommodations). It has given them profiles and characteristics that are completely different from those we had known until now, and as such, governments must give them special attention. One of the notable innovations that have accompanied the phenomenon of collaborative accommodations is how it affects the territorial scope of this economic activity. Until now, tourism was an especially self-contained sector, restricted to so-called “tourism areas” with defined urban boundaries related to specific kinds of buildings (basically hotels and apartments). Nowadays, it is clear that tourism supply and demand have crossed these boundaries, seeped into the fabric of cities and become mixed with the residential topologies that exist in urban areas (single-family and multi-family residences). All of this has led to notable negative impacts on the urban environment and housing policies. 1 This article is a summary of a more extensive piece of work published in the Revista de Administración Pública (number 205;2018). Furthermore, the creation of the present article was done under R&D project number DER2017-85624-C3-2-R of Spain’s Ministry of Economy, Industry and Competitiveness titled “The sustainable tourism city: responsible tourism, housing policy, and planning of the urban space” (“ La ciudad turística sostenible: turismo responsable, política de vivienda y ordenación del espacio urbano ”).