To combat SMS phishing (smishing) and boost mobile security, the Spanish National Markets and Competition Commission (CNMC) has introduced strict regulations under Order TDF/149/2025.
While the official national framework begins rolling out earlier, you must complete your registration by September 15th, 2026, to ensure your business is fully ready and compliant. After this deadline, Spanish mobile carriers will automatically block any business messages sent using an unverified “Alias” or Sender-ID.
To continue reaching your Spanish audience without disruption, you must register your Sender-IDs through an authorized provider.
The CNMC enforces strict formatting rules. If your Sender-ID does not match these specifications, carriers will reject it:
| Feature | Requirement |
| Length | 3 to 11 characters. |
| Allowed Characters | Letters (a-z, A-Z, including ñ and ç) and numbers (0-9). |
| Special Characters | @, &, ., -, _, + and spaces (cannot be at the start or end). |
| Prohibited Characters | Accents (á, é, etc.), symbols (e.g., !, ?, #, %, *, €), or brackets. |
| Naming Policy | No generic names (e.g., “SMS”, “Alert”). No numeric-only IDs. |
To complete your registration, you must submit two mandatory items: a Registration Form and a Letter of Authority. Both are strictly required to prevent your traffic from being blocked.
To comply with Spanish law, you must submit the official Spanish version of the Letter of Authority. We have provided English translations below to help you understand the requirements.
To register an Alias, you must prove you have the legal right to use it and that it directly identifies your brand. You will need to provide at least one of the following pieces of evidence:
We also require a signed declaration from you confirming that all provided information is true and accurate.
If you are a Spanish business or citizen you should be able to register yourself. If that is not the case we can manage the submission process directly with the regulator on your behalf. To do this, we collect documentation to confirm your business identity and valid aliases.
Yes. The rules apply identically to SMS, MMS, and RCS to ensure total channel security. These regulations do not apply to WhatsApp.
If your company is based outside Spain but sends messages to Spanish numbers (+34), you must use an authorized local provider. International routes that are not authorized by the regulator will be blocked.
Sender-IDs can be registered for an indefinite period. However, if an Alias remains inactive for 12 consecutive months, the CNMC may cancel the registration.
If you have any questions or want to start your registration immediately, please reach out to our support team or call us directly on our support number.
