The Spanish Communications Authority ( CNMC) is introducing a new SMS Sender ID register for all SMS, MMS and RCS messages sent to Spanish numbers (+34).
The regulation is based on the Ministerial Order TDF/149/2025 and the proposal Circular X/2026, which defines the use of SMS Sender ID.
The new rules are due to enter into force from 15.9.2026. After that date, messages sent with non-registered sender information will be blocked. This applies to SMS, MMS and RCS messages sent to Spanish numbers, country code +34.
What will change?
Current situation:
- The alphanumeric sender IDs (alias / SenderID) can be used without registration.
New regulation:
- All alphanumeric call signs must be registered and approved before use.
- Unregistered sender IDs are blocked by operators.
Who is affected by the change?
- All companies (Spanish and international) that send SMS, MMS or RCS messages to Spanish numbers (+34).
Sender name protection requirements
SMS / MMS
- Length: 3-11 characters
- Allowed signs:
- Letters (a-z, A-Z, ñ, ç)
- Numbers (0-9)
- Space
- Special characters: @ & – . +
Not allowed:
- Spaces at the beginning/end or consecutively
- Several special characters (e.g. #, %, (), ,, /, :, ;, , =, ¡, !, ¿, ?, [], €.)
- Just the numbers
RCS
- The sender ID must be clearly associated:
- to the brand
- the name of the company
- to the domain
Not allowed:
- Just the numbers
- Unclear or misleading names
If your company sends or plans to send messages to Spain: