Sales calls in Spain switch to 400 numbers on Saturday

Across Spain, sales calls get a new way to spot them on Saturday, 17 October: companies must use nine-digit phone numbers beginning with 400. People receiving a call can recognise it as a sales call before answering.

Why a 400 number cannot be called back

The new numbers work in one direction only. A person can receive a call from a 400 number but cannot ring it back. The rule is intended to help prevent fraud when people return calls to unfamiliar numbers.

Phone operators will also block calls when patterns, such as an unusually high volume, suggest sales activity. Anyone who receives a sales call from a different type of number can complain to the Oficina de Atención al Usuario de Telecomunicaciones, Spain’s telecoms user support office, or report it to the Comisión Nacional de los Mercados y la Competencia, the national markets and competition commission.

The wider crackdown on calls and messages

The 400 rule forms part of Spain’s measures against phone and text-message scams. Since the plan began in 2025, its measures have blocked more than 400 million calls and nearly 32 million fraudulent messages.

A separate register covers the sender names that companies and public bodies display on messages. Since September, operators have blocked more than six million messages using an unregistered name or one registered to someone else. People can check who owns a registered sender name on the competition commission’s website.

Calls about existing contracts are treated differently: customer service teams can still use specified short numbers, free 800 or 900 numbers, or numbers tied to a geographic area.

Source: Europa Press / Mallorca.com