# Spain mandates 400 prefix for commercial calls 16 October 2026 at 10:23 > New consumer protection laws require Spanish companies to use a specific 400 prefix for marketing calls starting from 17 October. A new measure under the **Ley de Servicios de Atención a la Clientela** requires commercial calls in **Spain** to use a **400 prefix** from 17 October. Operators must block any public marketing calls not using this nine-digit code, which functions unidirectionally. The law applies to essential sectors including energy, finance, and transport, alongside firms with over 250 staff or 50 million turnover. Small utility providers are exempt based on market share. The prefix prevents recipients from making return calls. The **OCU** warns this change does not guarantee call legality or eliminate spam. The consumer group is now calling for a public registry to identify companies behind each 400 number, as the new legislation enters its six-month transposition period today. [#SpainNews]() [#ConsumerRights]() #Telemarketing [#OCU]() #SpamCalls ## Related news ## [Spain orders removal of 8,318 illegal rental ads]() 23 October 2026 at 09:38 ## [Spain expands widow's pension for cohabiting parents]() 20 October 2026 at 09:21 ## [Magnitude 4.2 earthquake hits Benuza in Leon]() 16 October 2026 at 09:29 ## [Spain to discuss 2027 minimum wage increase]() 7 October 2026 at 16:48 ## [Spain probes real estate portal over rental ads]() 7 October 2026 at 09:43