Spain Strikes Back Against Scam Calls with New 400 Prefix

On 17 October 2026, Spain enacted a new regulation mandating that all commercial telephone calls originate from a nine-digit number beginning with the prefix 400. Telephone operators are mandated to block any commercial calls originating from mobile numbers, geographical landlines, or toll-free 800 and 900 numbers. The new 400 prefix will be one-way, allowing companies to reach customers but preventing recipients from returning the call.

Customers have the option to request their telephone provider to block any calls from the 400 range. The Telecommunications User Service Office and Spain’s competition and markets regulator, the CNMC, are empowered to receive reports of commercial calls from non-400 numbers. However, the new prefix does not grant companies the authority to call anyone at their discretion.

Businesses must adhere to Spain’s data-protection and marketing regulations, obtaining consent or having a valid legal reason for contacting individuals. Customer-service calls will continue to be permitted from approved short numbers, free 800 and 900 numbers, or geographical landline numbers, but ordinary mobile numbers cannot be employed.

This measure is part of the Spanish Government’s ongoing campaign against telephone and text-message fraud, which has already seen over 192 million suspicious calls and 17 million fraudulent text messages blocked since the anti-scam program commenced in March 2025. Additionally, Spain is establishing an official database of company and public entity names and codes used in text messages, blocking unregistered identities to prevent criminals from masquerading as banks, businesses, or government organizations.