United Kingdom (GB)

Locale name

United Kingdom

ISO code
The International Organization for Standardization two character representation for the given locale.

GB

Region

Europe

Mobile country code
A three digit code associated with the given locale and used in conjunction with a Mobile Network Code to uniquely identify mobile networks.

234, 235

Dialing code
The dialing prefix used to establish a call or send an SMS from one locale to the given locale.

+44

Two-way SMS supported
Whether Twilio supports two-way SMS in the given locale.

Yes

Number portability available
Whether number portability is available in the given locale.

Yes

Twilio concatenated message support
Concatenation refers to the capability of splitting a message that is too long to be sent in one SMS into smaller pieces and then joining the pieces at the receiving end so that the receiver sees the message as one. 

Yes*
For certain sender ID types this may not be supported. Where messages are split and rejoined may vary based on character encoding.

Message length
How many characters can be sent given a particular message encoding before the message will be split into concatenated segments.

Inbound: GSM 3.38=160, Unicode=70 Outbound: GSM 3.38=160, Unicode=70

Twilio MMS support
Multimedia Messaging Service (MMS) provides a standards-based means to send pictures and video to mobile phones.

Converted to SMS with embedded URL

Sending SMS to landline numbers
How Twilio handles an SMS message destined for landline telephone number.

Twilio will not check whether the number is a landline and will attempt to send it to our carrier for delivery. Some carriers will convert the SMS into text-to-speech messages via voice calls.

Compliance considerations
Twilio strongly encourages customers to review proposed use cases with qualified legal counsel to make sure that they comply with all applicable laws. This table lists some general best practices.

SMS-to-voice functionality is in widespread use in the UK, and as a result, Twilio will not reject messages sent to landlines. Please be aware of this fact because it may not be the desired behavior for your application. If this is not the desired behavior, Twilio Support can help.

Twilio strongly encourages customers to review proposed use cases with qualified legal counsel to make sure that they comply with all applicable laws. The following are some general best practices:

1. Get opt-in consent from each end user before sending any communication to them, particular for marketing or other non-essential communications.
2. Only communicate during an end user's daytime hours unless it is urgent.
3. SMS campaigns should support HELP/STOP messages, and similar messages, in the end user's local language.
4. Do not contact end users on do-not-call or do-not-disturb registries.

Operator network capability
Whether mobile operators in the given country support the feature.

Not Required

Supported

Twilio supported
Whether Twilio supports the feature for the given country.

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Supported
Learn more

Sender ID preserved
In some countries sender IDs for certain sender types are not preserved and are changed for compliance and/or deliverability reasons. In these countries mobile subscribers will see a different ‘from sender ID’ than the one sent by you.

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Yes

Provisioning time
Provisioning is the process of getting the sender ID approved and registered with mobile networks (depending on country requirements). Provisioning time is how long this process takes in the given country.

N/A

N/A

UCS-2 support

N/A

Supported

Use case restrictions

N/A

The use of generic Sender IDs should be avoided as they are being blocked from the operators.

Best practices

N/A

Please refrain from using generic sender IDs like SMS, TEXT, InfoSMS, INFO, Verify, Notify etc to avoid being blocked by network operators.
Twilio suggests using an Alpha Sender ID that is related to the content of the message.

Operator network capability
Whether mobile operators in the given country support the feature.

Supported

Not Supported

Supported

Twilio supported
Whether Twilio supports the feature for the given country.

Supported

Not Supported

Supported

Sender ID preserved
In some countries sender IDs for certain sender types are not preserved and are changed for compliance and/or deliverability reasons. In these countries mobile subscribers will see a different ‘from sender ID’ than the one sent by you.

Yes

N/A

Yes

Provisioning time
Provisioning is the process of getting the sender ID approved and registered with mobile networks (depending on country requirements). Provisioning time is how long this process takes in the given country.

N/A

N/A

8-12 weeks

UCS-2 support

Supported

N/A

Supported

Use case restrictions

Virgin Mobile no longer support SMS to UK landline numbers

Several UK networks, with EE, Telefonica and SKY being the most notable ones, are actively filtering A2P traffic submitted from International Longcodes. It is strongly recommended to avoid sending from International Longcodes to prevent blocking or filtering. Twilio will stop supporting International Longcodes starting from the 1st of June of 2023

Short codes can only message users on carriers within the countries in which they are provisioned. AlthoughTwilio can provision short codes in multiple countries, if your customers are not located in the UK, you should not obtain a UK short code.

Short codes require express consent from end users before any SMS can be sent; if you cannot obtain consent then you should not use a short code.

Twilio and/or the carriers will not support certain types of campaigns, including: 

• Those in which express end-user consent cannot be obtained. This includes friend-to-friend invite-based campaigns, as well as opt-ins obtained through lead generation.
• Those containing sexual/adult content (which is prohibited by Twilio’s AUP).

Note: Campaigns dealing with age-restricted content (cannabis, alcohol, gambling, etc.) are allowed, but will be evaluated on a case-by-case basis by UK carriers.

Best practices

N/A

It is strongly recommended to use Alphanumeric Sender ID when sending one-way Application-To-Person (A2P) traffic to the United Kingdom (UK). To support two-way requirement to carry on a conversation, Twilio offers Shortcode and Domestic Longcodes.

Refer to our FAQ for short code best practices: https://support.twilio.com/hc/en-us/articles/223134887-Requirements-for-UK-short-codes.