Spain to Launch 400 Prefix to Help Spot Spam and Business Calls

New 400 Prefix for All Business Calls

From October 2026, all business calls in Spain will be required to use a new 400 prefix, under regulations introduced by the Ministry for Digital Transformation and Public Administration. The move is designed to make commercial calls — including the unsolicited sales and spam calls that plague millions of residents — instantly recognisable on your phone screen.

The new 400 numbers will comprise nine digits in total. Minister Óscar López confirmed that telecom operators must ensure businesses use only numbers within this assigned block for all commercial calls. "This will make the calls immediately recognisable and improve the control and management of public numbering resources," he stated.

One-Way Only: No Call-Backs

In a smart anti-fraud design feature, the new 400 numbers will operate in one direction only — they can make outgoing calls to you, but you cannot call them back. This is specifically intended to reduce the risk of fraud associated with returning calls to unfamiliar numbers, a common scam tactic where victims are charged premium rates or tricked into sharing personal information.

If you see a 400 number on your phone, you will know immediately that it is a commercial call — and you can choose whether to answer or ignore it accordingly.

Existing Customer Service Numbers Unaffected

The existing 800 and 900 number ranges will continue to function as customer service lines with full two-way communication. These numbers allow consumers to contact businesses directly and will not be affected by the new regulations.

In short: 400 numbers are for businesses calling you. 800 and 900 numbers are for you calling businesses.

Cracking Down on Fake SMS Messages

Alongside the 400 prefix, the government has been escalating its efforts against fraudulent communications more broadly. Recent measures have already resulted in:

• 192 million fraudulent calls blocked
• 17 million fraudulent SMS messages blocked

Starting June 7, 2026, the CNMC (Spain's National Markets and Competition Commission) will establish an official registry of organisations authorised to send bulk SMS messages. This registry will cover companies, public bodies, and other entities permitted to contact users via text.

The initiative specifically targets identity theft in mass messaging — the fake texts that appear to come from your bank, energy company, or a government body like the Agencia Tributaria, but are actually phishing scams.

Minister López noted: "SMS messages impersonating companies, banks, energy companies, or government entities, which were all fake, will no longer be sent."

What This Means for Residents and Expats

For anyone living in Spain — whether Spanish nationals or expats — these changes should make daily life a little less frustrating and a little safer:

• From October: Any call from a 400 number is a business call. Answer or ignore as you see fit
• From June: Fake SMS messages impersonating banks and institutions should become significantly rarer
• Existing numbers: 800/900 customer service lines continue working as normal

This article is based on reporting from Spanish News Today, published April 17, 2026. Implementation dates are as announced by the Ministry for Digital Transformation and Public Administration and may be subject to change. This article is for informational purposes only.