Spain has introduced new regulatory requirements governing the use of alphanumeric Sender IDs for SMS, MMS, and RCS messages. These requirements establish a mandatory registration framework designed to help prevent sender impersonation, SMS fraud (smishing), and unauthorized use of business identities.
Organizations sending SMS, MMS, or RCS messages to Spanish telephone numbers using alphanumeric Sender IDs should review these requirements to help avoid message blocking and service disruptions.
1. Sender ID Registration Requirements
Beginning 15 September 2026, organizations using alphanumeric Sender IDs for SMS, MMS, or RCS messages sent to Spanish telephone numbers must ensure those Sender IDs are registered in accordance with the applicable regulatory requirements.
Spanish mobile network operators are required to block message traffic that uses unregistered or unauthorized Sender IDs.
Registration Deadline
The registration requirements become enforceable on 15 September 2026.
Organizations should complete the registration process before this date to help ensure uninterrupted message delivery.
2. Regulatory Framework
Spain's Sender ID registration requirements are established through the following regulations:
Ministerial Order TDF/149/2025
This Order establishes the legal obligation to register alphanumeric Sender IDs (aliases) and requires participating mobile network operators to block SMS, MMS, and RCS traffic that uses unregistered or unauthorized aliases.
CNMC Circular 1/2026
Published by Spain's National Commission on Markets and Competition (CNMC), this Circular defines the operational procedures governing the Alias Registry, including registration workflows, validation requirements, and technical implementation.
3. Registration Requirements
Organizations requesting an alphanumeric Sender ID should be prepared to demonstrate their right to use the requested alias.
Examples of acceptable supporting documentation include:
- A registered trademark.
- The organization's registered legal name.
- A registered internet domain corresponding to the requested Sender ID.
4. Registration Process
Organizations may register alphanumeric Sender IDs either directly through the CNMC Alias Registry (where eligible) or through an authorized representative, depending on their circumstances.
Note: For detailed registration instructions, eligibility requirements, and the documentation required for each registration method, see How to Register an Alphanumeric Sender ID in Spain.
5. Compliance Checklist
Before sending SMS, MMS, or RCS messages using an alphanumeric Sender ID to Spanish telephone numbers, verify that: