It has probably happened to you before: your phone rings, you see a number you don’t recognize, you think it might be a family member or something urgent… and it turns out to be a sales call. Sometimes it’s even worse: a scam attempt. That moment of uncertainty will soon disappear in Spain, as the Government has approved a new measure that completely changes the rules for commercial calls.<\/p>\n\n\n\n
Spain’s Ministry for Digital Transformation and the Civil Service has published a resolution establishing that, from October, all commercial calls must be made from a nine-digit number beginning with the 400<\/strong> prefix.<\/p>\n\n\n\n The idea is straightforward: as soon as you see a number starting with 400 on your screen, you’ll immediately know that a business is calling you for commercial purposes.<\/p>\n\n\n\n There is one important detail to understand: these numbers will be one-way only<\/strong>. In other words, customers will be able to receive calls from these numbers but will not be able to call them back. This is no coincidence\u2014it is designed to reduce the risk of fraud that occurs when people return calls to unknown numbers, a common tactic used in telephone scams.<\/p>\n\n\n\n One point worth noting is that an earlier draft of the regulation, published in February, proposed making these numbers two-way. However, the final version approved in April changed this approach and established them as one-way numbers. If you’ve read otherwise elsewhere, it was most likely referring to the earlier draft.<\/p>\n\n\n\n The new numbering range will become operational within six months of the publication of the resolution. From October 2026<\/strong>, telecommunications operators will begin blocking commercial calls that do not use the 400 range.<\/p>\n\n\n\n From that point onward, any commercial call made from a number other than one beginning with 400 may be blocked directly by the telecom operator, without the user having to take any action.<\/p>\n\n\n\n This measure does not come out of nowhere. It implements the Customer Service Act (Ley SAC)<\/strong>, approved in December 2025, which already required commercial calls to use a dedicated numbering code so they could be clearly identified.<\/p>\n\n\n\n This is where some confusion often arises, so it’s worth clarifying.<\/p>\n\n\n\n The 400 prefix is exclusively for commercial calls<\/strong>\u2014those made by a company to sell products or services or acquire new customers.<\/p>\n\n\n\n Customer service calls\u2014those related to an existing contract, support request or incident\u2014follow different rules. These may only be made from specifically assigned short numbers, the free 800 and 900<\/strong> ranges, or standard geographic numbers.<\/p>\n\n\n\n This requirement was already established by the ministerial order aimed at preventing caller ID spoofing, which came into force in March 2025 and also prohibited the use of mobile numbers for this type of customer service call.<\/p>\n\n\n\n In short:<\/p>\n\n\n\n The objective is clear: to combat telephone fraud.<\/p>\n\n\n\n Digital Transformation Minister \u00d3scar L\u00f3pez<\/strong> summed it up well by saying that everyone has answered a call believing it was someone they knew, only to discover it was a commercial call.<\/p>\n\n\n\n The new numbering system forms part of a broader national strategy against telephone fraud. According to the latest official figures, since the plan was introduced in March 2025 it has enabled operators to block 192 million fraudulent calls<\/strong> and 17 million fraudulent SMS messages<\/strong>. These numbers illustrate the scale of the problem the Government is seeking to address.<\/p>\n\n\n\n This is where the new regulation directly impacts contact centers, telesales teams and any organization running outbound telemarketing campaigns.<\/p>\n\n\n\n The change involves far more than simply replacing a phone number. Businesses will need to review their outbound calling infrastructure, adapt their dialing platforms and ensure that every commercial campaign is carried out exclusively using numbers within the new 400 range.<\/p>\n\n\n\nWhen Will It Become Mandatory?<\/h2>\n\n\n\n
What About Customer Service Calls?<\/h2>\n\n\n\n
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Why Has the Government Introduced This Measure?<\/h2>\n\n\n\n
What Does This Mean for Companies That Make Commercial Calls?<\/h2>\n\n\n\n