Is a holiday let registered at this address?

Before tourist letting begins, a declaration must be submitted to the region; registration follows this declaration, not the other way round. That says what an entry proves. It also says why a number should appear in the listing at all: except in Andalusia, every one of these regions requires it in advertising.

Comunitat Valenciana

In the Comunitat Valenciana, the start of tourist letting must be notified to the tourism administration by a notification or a self-declaration (comunicación, declaración responsable); once it has been received, the property is entered ex officio in the Registro de Turismo de la Comunitat Valenciana. Every advertisement for a holiday property must state its exact location and the number of this registration. The registration is valid for five years. (Art. 53.2, 77.5, 19.1 b) und 65.4 Ley 15/2018, consolidated version, last updated 02.07.2026)

Catalonia

In Catalonia, a holiday property needs the authorisation provided for by the applicable law (título habilitante) before the activity starts; anyone who offers, markets or advertises the accommodation must also have it. The number of the entry in the Registre de Turisme de Catalunya must appear in all advertising, promotion and marketing. (Art. 50 bis.2 und 73.5 Llei 13/2002, consolidated version, last updated 17.03.2023)

Andalusia

In Andalusia, a self-declaration (declaración responsable) must be submitted to the tourism administration before letting starts; from that point the property may be advertised as a vivienda de uso turístico, and the entry in the Registro de Turismo de Andalucía is made ex officio on the basis of this declaration. (Art. 38.2 Ley 13/2011; Art. 9.1 Decreto 28/2016 in der Fassung der Disposición final sexta des Decreto-ley 1/2025, consolidated version, last updated 03.03.2025; the version of Decreto 28/2016 applies since 04.03.2025)

Mallorca and Menorca

In the Balearic Islands, a declaration of the start of tourist activity must be submitted before the activity begins (declaración responsable de inicio de actividad turística, DRIAT); it entitles the holder to carry out the activity from the day of submission, and submission leads directly to entry in the island's register. The registration number must be stated in advertising; as long as it has not yet been assigned, the receipt number of the declaration is sufficient. For properties in divided ownership, the declaration entitles the holder for the period set by regulation, or, without such a provision, for five years from submission. (Art. 23.2, 23.3, 23.6, 23.7 und 50.3 Ley 8/2012, consolidated version, last updated 13.06.2026; Art. 50 in force since 09.07.2025)

Canary Islands

In the Canary Islands, a self-declaration (declaración responsable) must be submitted to the island's Cabildo before letting starts; it entitles the holder to carry out the activity from the day of submission, and the Cabildo enters it ex officio in the Registro General Turístico. The entry contains a registration number, which must be stated in every advertisement, including on booking platforms. The declaration is valid for five years, and for ten on El Hierro, La Gomera and La Palma and in municipalities facing demographic challenges (municipios de reto demográfico). (Art. 7.1, 8.1, 8.6 und 10.1 Ley 6/2025, version of 12.12.2025; Art. 7 was only supplemented by a paragraph on occasional letting by the Disposición undécima of Ley 7/2026 (BOC no. 163 of 14.08.2026))

This is the statutory text in the version linked here. For an individual property, the information given by the competent authority — the region's tourism register and the municipality — is authoritative.

If the seller gives a registration number, that is the more precise route: the number matches exactly one entry, whereas comparing the address can fail because of a different spelling of the street.