In recent years, Spain has played a prominent role in the standardization and establishment of standards in the field of smart cities, particularly in the area of smart tourism. Standardisation was one of the strategic pillars of the National Smart Cities Plan, and the Spanish Association for Standardization (UNE) established in 2012 the Standards Committee CTN 178 ‘Smart cities’, initially promoted by the Secretary of State for Telecommunications and the Information Society. The Ministry of Tourism, through SEGITTUR, promoted the creation of the Subcommittee 5 ‘Smart Destinations’ (SC5) within it with the aim of creating a consistent framework for smart tourism destinations. Through the Standards Technical Committee CTN-UNE 178 and the set of standards from Subcommittee 5 ‘Tourist Destinations’, Spain has led the creation of standards related to smart tourism destinations. Additionally, it has closely collaborated with other standardization entities such as the International Telecommunication Union (ITU) and the International Organization for Standardization (ISO). Some of these standards, such as UNE 178104 on interoperability of smart city platforms or UNE 178503 on semantics applied to tourism, have gained broad international following and have led to further works in the Initiative of United Nations ‘United for Smart Sustainable Cities’ (U4SSC) related to UN Sustainable Development Goals. This chapter analyzes the role of Spain in the standardization of smart city destinations, highlighting the reasons for their creation and providing an overview of the structure, as well as the advantages of these standards and their impact in the global context.