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SMS Guidelines for South Korea: Best Practices and Compliance

When sending SMS messages to South Korea, it's crucial to adhere to specific guidelines to ensure compliance and successful message delivery. This article outlines key SMS regulations, encoding requirements, and best practices for businesses and developers targeting the South Korean market.

Key SMS Regulations in South Korea

South Korea enforces strict guidelines for SMS communication, particularly for Application-to-Person (A2P) messaging. Here are the essential regulations:

  • Two-way SMS Support: Unfortunately, two-way SMS is not supported in South Korea, meaning users cannot reply to your SMS messages.
  • Numeric Sender ID: Only numeric sender IDs are permitted, automatically prefixed with "009" or "006" to comply with South Korean regulations.
  • Message Tags: SMS messages sent to South Korea will automatically include either "[Web 발신]" (A2P) or "[국제발신]" (international) to indicate the message type.
  • Character Encoding: Only EUC-KR characters are supported by South Korean mobile operators. Ensure your content uses only characters from the EUC-KR set.
  • Prohibited Content: Sending adult or gambling-related content is strictly prohibited, with non-compliance resulting in penalties or message blocking.

Message Length and Encoding

The message length and encoding are critical for SMS delivery in South Korea:

  • GSM Encoding: One SMS segment can hold up to 140 characters using GSM 8-bit unpacked encoding (commonly referred to as ASCII).
  • UCS2 Encoding: Messages with special characters use UCS2 encoding, reducing the message length to 70 characters per segment.
  • Concatenated Messages: Long messages are not supported. Messages exceeding the character limit will be delivered as multiple separate segments.

MMS Support

Multimedia Messaging Service (MMS) is not directly supported in South Korea. Instead, MMS content is converted into an SMS with an embedded URL, allowing recipients to access multimedia content via a link.

Sending SMS to Landline Numbers

Sending SMS to landline numbers in South Korea is unsupported. Attempts to send an SMS to a landline will result in a 400 error response with code 21614, with no charges applied.

Compliance Considerations and Best Practices

To ensure compliance with local regulations in South Korea, follow these best practices:

  • Opt-In Consent: Obtain explicit opt-in consent from users before sending any communications, especially marketing or non-essential messages.
  • Respect Time Zones: Send SMS messages during the recipient’s local daytime hours unless the message is urgent.
  • Support for HELP/STOP Messages: Ensure your SMS campaigns support standard HELP/STOP commands in the recipient's local language for preference management.
  • Do-Not-Call Registries: Avoid contacting users registered on do-not-call or do-not-disturb lists.
  • Legal Review: Review your SMS use cases with qualified legal counsel to ensure compliance with South Korean laws.

Conclusion

Navigating the SMS landscape in South Korea requires careful attention to local regulations, encoding standards, and message content restrictions. By adhering to these guidelines and best practices, businesses can ensure their SMS campaigns are effective, compliant, and well-received by South Korean users.

Consult with legal experts and thoroughly review your SMS content to avoid potential issues. With the right approach, SMS can be a powerful communication tool in the South Korean market.

For more information on SMS regulations, visit the Korea Communications Commission official website.