It was previously regulated by the Comisión del Mercado de las Telecomunicaciones (CMT), but is now regulated by the Comisión Nacional de los Mercados y la Competencia (CNMC).

[5] However, on 17 December 1994, Andorra adopted its own country code +376, with '8' being added to the subscriber's five-digit number, meaning that international dialling was required from Spain, e.g.:[6] Mobile phone numbers began with the prefix '90x' or '9x9', e.g.:[7] On 1 December 1998, Spain changed to a new telephone numbering plan.

[11] In addition, it was possible to call Gibraltar from other countries via Spain using the prefix +34 9567.

[13] Consequently, numbers with the prefix 9567 were withdrawn from use, and made available for reassignment to subscribers in Spain.

Since the blocks of mobile phone numbers are allocated according to demand from the service providers, there is not necessarily a unique service provider indicated by the three digit numbering group (6xx or 7yx).