400 Numbers: Spain's New Law Changing Commercial Calls
And how to prepare your business before October
The introduction of 400 numbers is one of the most significant changes to telephone-based commercial communications in Spain in recent years. Beyond the technical adaptation businesses and operators will need to make, this measure opens up a wider debate: how to tackle the practices that have damaged the reputation of telesales, without penalising the many companies that operate legitimately and in full compliance with the law.
What does the new 400 numbering mean?
The new numbering was created to make commercial calls placed by businesses more clearly identifiable to the people receiving them. Its main features:
- It is reserved specifically for commercial communications.
- These are outbound-only numbers: a 400 number cannot be called back.
- Operators must inform their customers about this numbering, clearly identify these communications, and provide tools to manage or restrict this type of call.
- The obligation takes effect on 17 October 2026 (Law 10/2025 on Customer Service, and the Resolution of 14 April 2026, BOE-A-2026-8409).
The aim is clear: give consumers more control and improve the transparency of commercial communications.
A few practical questions still to be settled
Despite this regulatory progress, several practical details will largely determine how well the measure works in practice.
1. How will these calls actually appear on the user's phone?
One of the biggest open questions is how the call will display to the person receiving it. Possible scenarios include a descriptive label such as “Commercial Call,” automatic classification through preventive tags like “Possible spam,” or verified caller-ID systems that show the calling company’s name — similar to models already used by some business messaging services. Whatever the final approach, the regulatory goal is clearly to make the commercial nature of the call obvious, leaving the decision of whether to answer to the user.
2. What happens to other legitimate high-volume calling activities?
Another important question concerns professional activities that, while not strictly commercial, involve a high volume of calls: appointment scheduling, surveys and market research, debt collection, customer support and follow-up, or service confirmations and reminders. It’s essential that automatic filtering and classification systems don’t end up penalising these legitimate activities by creating unnecessary operational barriers.
The real goal: tackling bad practice
From our point of view, the spirit of the regulation is simple: the person receiving the call should have enough information to decide whether to answer a commercial call. Transparency benefits both consumers and the businesses that operate correctly. That’s why rolling out 400 numbers should go hand in hand with measures that actively favour companies that comply with the rules and operate to high standards of quality and responsibility.
Turning regulation into a competitive advantage
For the measure to achieve its goals, compliance should generate tangible benefits, such as:
- Business identity certification: a verification system confirming the calling company’s identity and the authenticity of the call, showing customers messages like “Verified commercial call from [company name].”
- Greater decision-making power for consumers, with clear, reliable and verifiable information about who is calling.
- Recognition of good business practice: regulatory compliance, jobs and services based in Spain, the quality of customer service and sales processes, and social responsibility policies.
- Greater pressure on non-compliant operators, through more effective controls and a deterrent penalty regime for those operating outside the law.
A challenge for the whole industry
When regulatory compliance adds costs without creating a competitive edge, some operators are tempted to look for ways around the rules — it’s a pattern seen time and again. The real problem facing the industry isn’t professional, properly regulated commercial calling; it’s the proliferation of low-quality operators that damage the consumer experience: repeated, unwanted calls, ignoring calling-hours limits or contact caps, using data obtained without proper consent, possible impersonation of legitimate businesses, and communications that aren’t transparent about the real reason for the call. These are the practices that have eroded consumer trust, and they should be the main focus of regulatory enforcement.
How to prepare your business before 17 October
Conclusion
400 numbers could become a decisive tool for improving transparency in commercial communications and rebuilding consumer trust. Their success will depend on how clearly they distinguish businesses that comply with the rules from those that keep operating outside them. The regulation will only be truly effective if it achieves two things at once: protecting consumers and creating a level playing field where responsible businesses can compete fairly.
