Spain restricts commercial calls to a new range of 400 numbers

Spain restricts commercial calls to a new range of 400 numbers

17 October 2026: Companies covered by Spain's customer service law may place commercial calls only from nine-digit numbers that begin with 400, a range the telecommunications ministry created for the purpose. Numbers in the range can dial out but cannot receive calls, so a sales team using one cannot also offer it to customers as a callback line.

Not yet independently verified. The go-live date is derived from the resolution (effects from 17 April plus six months) and is stated by Xataka, not by a ministry page. The text of Ley 10/2025 and its separate 28 December 2026 customer service deadline were not checked against the law itself. We will update this when it can be confirmed, and remove this note.

A resolution with a six-month fuse

The rule comes from a resolution dated 14 April 2026 and signed by Antonio Hernando Vera, the Secretary of State for Telecommunications and Digital Infrastructure at the Ministry for Digital Transformation and the Civil Service. It appeared in the BOE, Spain's official gazette, on 16 April 2026 and took effect the next day. Its legal basis is article 16.3 of Law 10/2025 of 26 December on customer service, together with article 27.7 of Royal Decree 2296/2004.

Section six gave the CNMC, the operators and the companies that make commercial calls six months to get the range fully operational. After that deadline, commercial calls may only be made from 400, and no other range. That deadline falls on 17 October 2026, the day Xataka reports the rule as applying. The law allows exceptions only through its single transitional provision.

What the range can and cannot do

The resolution attributes code 400 of the national numbering plan to commercial calls. The conditions are narrow:

• numbers are for outgoing commercial calls only, with no incoming calls
• they cannot be used for customer service or any other purpose
• calls from the range count as originating from a fixed access for interconnection
• calls from a 400 number may only terminate on end-user numbering: geographic, mobile and nomadic voice numbers

Operators must open the range in their networks, but establishing a call to any 400 number is prohibited. They must also publicise the range during the fifth to eighth month after entry into force, and they may offer customers an option, on request, to disconnect commercial calls made from it.

Who can hold the numbers

Only operators of publicly available telephone services, or an equivalent category the CNMC sets, can obtain 400 numbers, and they must make them portable. A company that dials from a virtual switchboard, an automatic dialler or a communications platform therefore depends on its provider having a block assigned. The CNMC supervises the scheme and set an initial assignment period during which the usual first-come, first-served order could be waived where justified.

What Xataka found on launch day

Xataka reports that the CNMC opened an initial 15-day window for operators to request numbers, first come first served, in blocks of 1,000. Movistar has the number 400 00 1004, and Digi has 400 120 120, 400 120 122, 400 120 131 and 400 120 134, which show on a phone screen labelled as a commercial call.

The outlet says operators are expected to block commercial calls that do not come from 400 by looking at traffic patterns. Users can complain to the consumer service body OAUT or report to the CNMC, and a service called SoyYo, backed by Repsol, Naturgy and Sabadell, lets people check who is calling. Xataka adds that spoofing of caller numbers remains possible, so the prefix does not by itself stop spam.

Customer service deadline

Xataka also reports that the law gives companies until 28 December 2026 to adapt their customer service. The BOE resolution itself states no penalties. A firm running sales campaigns through a dialler or CPaaS service should confirm that its provider has 400 numbers assigned and that the campaigns run from them, which is Xataka's reading of the rule rather than something the resolution spells out.

Sources

• BOE: Resolution of 14 April 2026 of the Secretaria de Estado de Telecomunicaciones e Infraestructuras Digitales (BOE-A-2026-8409), 16 April 2026
• Xataka: hoy entra en vigor el prefijo 400, 17 October 2026