SMS Regulations You Must Know to Send SMS in The UK

UK mobile networks are introducing additional restrictions in respect of SMS sender IDs in order to reduce the risk of spam/spoofed messages.

As of 1st June 2023 the following amended rules shall apply.

• Messages containing sexual/adult content are prohibited.
• Marketing messages should also have a clear opt-in and opt-out procedure.

The use of International Numbers for A2P messages is being blocked by the UK Mobile Network Operators.

In addition, unauthorized variants of legitimate SenderIDs, i.e. Sender IDs belonging to banks and government agencies as well as generic, non-branded Sender IDs (eg. “Verify”, ”OTP”, ”Code”, etc.), are also being filtered.

Therefore it is required to use a branded, Alphanumeric Sender ID and/or UK Domestic numbers for your A2P messages.

Sender ID allowable characters to include only:

• A to Z (Uppercase),
• a to z (Lowercase),
• 0-9,
• Maximum of 11 allowable characters
• Sender ID’s needs to be to pre-registered

Note: SenderID registration is NOT required to most other European countries!

Sender ID Registration

To start registration login to our dashboard.

• Go to "Send SMS"
• Click on "Sender"
• A pop-up will show where you can enter your registration data
• Sender ID: 11 characters long, no spaces or special characters
• Enter your website, senderID (matching with your business name) and other information

Examples:

If your company name is "John Doe Ltd" your senderID will become "JohnDoe"

Do not add "test" or anything generic as a SenderID because it will likely get rejected.

It will take about 2 work days to get approval; contact support if require urgency!

Updated on: 27/10/2025