Sending international B2C SMS (often called A2P SMS – Application-to-Person) requires balancing compliance, deliverability, and customer experience. Although regulations and some practices might differ from country to country, there are some general guidelines you should consider.
Explicit opt-in is required
For all international B2C SMS, explicit consent from recipients is a fundamental requirement for A2P SMS messaging. In many markets, companies implement double opt-in mechanisms (for example, users enter their phone number and confirm their subscription by replying to a verification message such as “Reply YES to subscribe”). While not always mandatory, double opt-in is widely considered a best practice for ensuring clear consent.
In addition to opt-in, businesses must always provide a simple opt-out mechanism, typically through keywords such as STOP, CANCEL, or UNSUBSCRIBE, although the exact requirements may vary by country and messaging provider.
Respect country-specific laws
There is no single global standard governing SMS messaging. Regulations, operator policies, and messaging requirements vary significantly from country to country. The most common differences include:
- Allowed sender ID formats
- Time-of-day restrictions for marketing messages
- Sender or campaign pre-registration requirements
- Content restrictions (e.g. gambling, financial services, political messaging)
For example, France restricts marketing SMS on Sundays and public holidays, while in the United States marketing messages must comply with the Telephone Consumer Protection Act (TCPA), which limits marketing texts to the hours between 8 a.m. and 9 p.m. local time.
Use local sender IDs or registered numbers
Using local or recognized sender IDs can significantly improve both deliverability and customer trust, as messages appear more familiar and legitimate to recipients. There are three options for sender IDs, but not all are available in each country:
- Alphanumeric sender ID (e.g. iBASIS”)
- Local long number (long code) – A standard phone number used for messaging, typically enabling two-way communication.
- Short code – A short number (typically 3–7 digits) used for high-volume messaging campaigns and usually requiring carrier approval and registration.
Some countries, such as the United States, do not allow alphanumeric sender IDs and require the use of registered numbers (for example through the 10DLC framework).
In many markets, businesses must also complete sender or brand registration with carriers or regulators before sending messages.
This process typically requires declaring the sender identity, message use case, and the phone numbers that will be used for messaging.
Reliable messaging providers can help businesses navigate country-specific requirements, manage sender registrations, and ensure high-quality routing through direct operator connections.
Maintain compliance records
Maintaining proper compliance records is essential for any international SMS program. Companies should retain logs that demonstrate user consent and messaging activity.
- Opt-in source (e.g. website form, mobile app, in-store signup)
- Opt-in timestamp
- Message content sent to the user
- Delivery and message logs
- Opt-out requests and processing records
These records can help demonstrate compliance if regulators investigate complaints or if carriers review and flag messaging traffic.
Use a reputable SMS gateway
Working with a reputable international messaging provider can help companies manage compliance and deliverability across markets.
Providers such as iBASIS offer services including routing optimization, sender ID management, delivery reporting, and support for country-specific compliance requirements.
Checklist for International SMS Programs
- Explicit recipient opt-in
- Respect local sending hours and regulations
- Use a registered or compliant sender ID
- Follow country-specific messaging requirements
- Maintain compliance and consent logs
- Work with a reputable messaging provider
For more information on how to run an SMS campaign, please consider our step-by-step guide.In international B2C messaging strategies, many companies also combine channels to improve engagement and optimize costs. For example, SMS is often used for urgent notifications or time-sensitive alerts, while richer or more interactive content can be delivered through channels such as RCS (Rich Communication Services).