SMS Pricing in South Korea: 2025 Provider Comparison & Cost Guide

Sending SMS messages to South Korea requires understanding carrier regulations, API provider costs, and compliance requirements. This comprehensive guide compares SMS pricing from leading providers (Twilio at $0.0494, Plivo at $0.03625, Sinch, and Infobip) with current 2025 rates, regulatory compliance details, and practical tips to help you select the most cost-effective SMS API solution for Korean business messaging.

South Korea SMS Market Overview

South Korea's SMS market blends domestic telecom giants with international SMS API providers. SK Telecom, KT Corporation, and LG U+ dominate the market, offering bundled SMS services alongside voice and data plans. International providers like Twilio, Plivo, Sinch, and Infobip cater specifically to businesses with specialized API-driven messaging solutions.

Practical differences: Domestic carriers bundle SMS into consumer voice/data plans (typically 100–300 free SMS per month) and charge per-message overage fees of approximately ₩20–30 ($0.015–$0.023 per exchange rates). International API providers like Twilio, Plivo, Sinch, and Infobip offer programmable A2P messaging with RESTful APIs, webhook callbacks, delivery tracking, and automated compliance handling – services unavailable through standard domestic carrier plans.

Key Market Dynamics

• Dominant Carriers: SK Telecom holds approximately 48.4% market share, KT Corporation holds 28.5%, and LG U+ holds 23.1% (2023 data). These three carriers control the entire South Korean mobile telecommunications market for consumer SMS services.
• International Players: Companies like Twilio, Plivo, Sinch, and Infobip focus on providing robust API solutions for businesses, often with more competitive per-message pricing for higher volumes. Typical pricing structure: International providers charge per-segment fees ($0.036–$0.049) plus optional monthly number rental (starting at $1.15/month for Twilio). Domestic carriers charge per-message overage fees after exhausting bundled SMS but lack programmable APIs for automation.
• Regulatory Oversight: The Ministry of Science and ICT (MSIT), Korea Communications Commission (KCC), and Korea Internet & Security Agency (KISA) regulate the telecommunications sector, ensuring fair competition and transparent pricing practices.
• OTT Messaging Apps: Over-The-Top (OTT) messaging apps like KakaoTalk (with over 47 million monthly active users in South Korea, representing over 90% smartphone penetration) significantly impact the consumer SMS market. However, business SMS remains critical for official notifications, two-factor authentication (2FA), marketing campaigns, and customer service interactions. Business SMS usage: According to industry data, South Korea's A2P SMS market was valued at $3.56 billion in 2024, demonstrating strong demand despite OTT dominance in peer-to-peer messaging.

SMS Pricing Comparison: How Much Does It Cost to Send SMS in South Korea?

Choose the right international provider by comparing pricing, features, and support across four major players:

Prices verified as of January 2025. Base rates vary based on volume and specific features. Contact providers directly for detailed quotes based on your projected usage.

Volume discount example (Twilio): Based on Twilio's U.S. volume tier structure, automatic discounts apply at: 150,001–300,000 messages (5–10% reduction), 300,001–500,000 messages (10–15% reduction), and 1,000,000+ messages (15–25% reduction). South Korea rates follow similar structures – contact Twilio for exact Korea-specific tiers.

Which SMS Provider Offers the Best Value for South Korea?

Twilio: Offers comprehensive API documentation and enterprise-grade security with scalable solutions for businesses of all sizes. Volume-based pricing tiers make Twilio cost-effective for high-volume senders. Typical use cases: Banking 2FA (financial institutions requiring SOC 2 compliance), enterprise notifications (10,000+ daily messages), SaaS product authentication. Twilio reports >99% delivery rates in South Korea when following local compliance guidelines.

Plivo: Emphasizes ease of integration with modern REST API architecture and provides excellent documentation and support. Competitive rates and flexible pricing structures make Plivo attractive for businesses seeking balance between cost and functionality. Typical use cases: Startup OTP delivery (500–5,000 messages/day), marketing campaigns for SMBs, appointment reminders. Customer testimonials report 9% deliverability improvement over previous providers.

Sinch: Maintains strong regional presence and established relationships with local carriers, delivering high success rates in South Korea. Expertise in Asian markets makes Sinch suitable for businesses prioritizing reliable message delivery. Typical use cases: E-commerce order updates, logistics tracking, regional campaigns requiring local carrier optimization. Sinch supports RCS Business Messaging alongside SMS for richer experiences.

Infobip: Stands out with highly competitive pricing and global messaging infrastructure. Advanced delivery optimization and comprehensive analytics dashboard provide valuable insights into messaging campaigns. Typical use cases: High-volume transactional messaging (50,000+ messages/day), multi-channel campaigns (SMS + WhatsApp + email), enterprises requiring detailed analytics and A/B testing capabilities.

Key Factors That Impact SMS Costs in South Korea

Several factors influence the final cost of SMS messages in South Korea:

• Domestic vs. International Routing: Messages routed within South Korea typically incur lower costs than internationally routed messages. Price difference example: Domestic routing through a local Korean aggregator may cost $0.025–$0.035 per message, while international routing (messages originating from servers outside Korea) costs $0.036–$0.049 – a premium of approximately 20–40% due to additional interconnect fees and mandatory prefixing with [국제발신].
• Local Carrier Agreements: Providers with strong partnerships with local carriers (SK Telecom, KT, LG U+) often offer more competitive pricing and better delivery rates.
• Regulatory Compliance: Adhere to regulations set by the MSIT, KCC, and KISA. Key compliance requirements include:
  • Message tags: SMS messages are automatically prepended with [Web 발신] (indicating A2P/application-to-person messages) or [국제발신] (indicating messages sent from abroad)
  • Sender ID format: Only numeric sender IDs are supported. International long codes are automatically prefixed with 009 or 006 by mobile operators
  • Character encoding: Only EUC-KR characters are supported by South Korean mobile operators
  • Content restrictions: Adult and gambling-related content is strictly prohibited
  • Message length: One SMS segment contains up to 140 bytes (140 characters using GSM 8-bit encoding or 70 characters using UCS2 16-bit encoding)
  • Concatenation: Long messages are no longer supported as concatenated messages and will be delivered as multiple separate segments
  • Consent requirements: Explicit written or electronic consent is required before sending marketing SMS, with records maintained for at least 3 years under the Personal Information Protection Act (PIPA)
  • Penalties for non-compliance: Under PIPA, violations carry fines up to ₩50 million ($37,000 USD) or five years imprisonment for unauthorized data transfers. Marketing SMS violations under the Network Act may incur fines up to 3% of related sales or ₩400 million ($300,000 USD). The KCC increased spam penalties in January 2024, with imprisonment for illegal spam senders extended from one year to up to three years.
• Message Volume: Higher message volumes unlock lower per-message rates through tiered pricing structures and bulk discounts. Example volume tiers:
  • 1–150,000 messages/month: Base rate ($0.036–$0.049/message)
  • 150,001–300,000 messages/month: 5–10% discount
  • 300,001–500,000 messages/month: 10–15% discount
  • 500,001–1,000,000 messages/month: 15–20% discount
  • 1,000,001+ messages/month: 20–30% discount (enterprise custom pricing)
• Service Model: Choose between pay-as-you-go, subscription, or hybrid models to affect overall costs. Pay-as-you-go offers flexibility but higher per-message rates, while subscriptions provide lower rates but require monthly commitments. Hybrid models combine elements of both. Cost comparison example: For 100,000 messages/month in South Korea: Pay-as-you-go at $0.0494/message = $4,940; committed-use discount at $0.038/message = $3,800 (23% savings); hybrid model with 50K prepaid base + overage = $2,400 + (50K × $0.042) = $4,500 (9% savings).

SMS Regulations in South Korea: Compliance Requirements

South Korea Sender ID Requirements and Restrictions

South Korea requires numeric sender IDs for all SMS messages. Alphanumeric sender IDs are not supported. International long codes are automatically prefixed with 009 or 006 by mobile operators to comply with Korean telecommunications regulations.

Valid sender ID formats:

• International long code: +14155551234 → displayed as 00914155551234 or 00614155551234 (automatic carrier prefix)
• Numeric-only format: All sender IDs must be numeric; no letters, special characters, or brand names are permitted

Invalid sender ID formats (will be rejected or converted):

• Alphanumeric: BRAND123, MyCompany, ABC-Corp (not supported in South Korea)
• Short codes from other countries: U.S. short code 12345 will be prefixed as 00912345 and may cause delivery failures

SMS Message Format Requirements for South Korea

All SMS messages to South Korea must comply with strict formatting and content requirements:

• Automatic message tags: A2P messages receive the [Web 발신] prefix, while international messages receive the [국제발신] prefix
• Character encoding: Only EUC-KR character encoding is supported. Handling special content: Emojis and Unicode characters outside EUC-KR (including Chinese characters) may fail to deliver or render as ? symbols. Latin alphabet (A-Z, a-z) and numbers (0-9) using GSM-7 encoding are supported. For Korean text (Hangul), use EUC-KR encoding exclusively. Test thoroughly across all three carriers (SK Telecom, KT, LG U+) before production deployment.
• Content restrictions: Adult content, gambling-related content, and certain promotional materials are strictly prohibited. Promotional content definition: Under KCC and KISA guidelines, "promotional materials" include any commercial advertisement for goods or services. Marketing SMS must include the header (광고) (meaning "advertisement") and footer opt-out instructions such as 무료수신거부 0808… with a toll-free opt-out number. Political campaigns (P2P traffic), cryptocurrency promotions, unauthorized pharmaceuticals, and religious promotional content are all prohibited. Grey-area content: Product announcements to existing customers may qualify as transactional (no (광고) header required) if directly related to prior purchases; however, upsell or cross-sell messages require the advertisement header and prior marketing consent.
• Consent compliance: Marketing messages require explicit written or electronic consent under PIPA, with records maintained for 3 years. Consent best practices: Implement double opt-in verification with timestamped consent logs. Consent forms must clearly state message purpose, frequency, and data usage in Korean. Required fields include: (1) explicit agreement checkbox (pre-checked boxes are non-compliant), (2) data controller identity and contact info, (3) retention period (typically 3 years or until opt-out), (4) third-party data sharing disclosures (if applicable), (5) withdrawal/opt-out instructions. Store consent records with user ID, timestamp (KST timezone), IP address, consent method (web form/email/SMS), and consent language version. Renew marketing consent every 2 years per PIPA best practices.

Regulatory Bodies

Three government agencies oversee SMS communications in South Korea:

• Ministry of Science and ICT (MSIT): Primary telecommunications regulator. Official website (English available). Handles telecom policy, spectrum management, and carrier licensing.
• Korea Communications Commission (KCC): Manages communications policy and compliance. Official website (Korean; select English for limited content). Enforces anti-spam regulations and investigates consumer complaints. Enforcement: The KCC announced increased penalties in December 2024 for illegal spam, including market-wide audits of mass texting services.
• Korea Internet & Security Agency (KISA): Oversees information protection and security. KISA Spam Reporting Center (Korean) allows consumers to report unsolicited SMS. Complaint process: Businesses receiving complaints may face investigations, corrective orders, and fines. Check numbers against KISA's Do-Not-Send Registry monthly to maintain compliance.

How to Choose the Right SMS Provider for South Korea

Evaluate SMS providers for the Korean market using these criteria:

• Evaluate Multiple Providers: Compare pricing, features, and support from several providers to find the best fit. Evaluation metrics: (1) Base per-message rate, (2) volume discount thresholds and percentages, (3) Korea-specific compliance features (automatic [Web 발신] tagging, EUC-KR encoding support), (4) delivery rate guarantees (target: >95%), (5) API response time (target: <500 ms), (6) webhook reliability for delivery receipts.
• Test API Integration: Test the API integration process thoroughly to ensure seamless compatibility with your existing systems. Example integration test (Twilio):

from twilio.rest import Client

# Twilio credentials
account_sid = 'YOUR_ACCOUNT_SID'
auth_token = 'YOUR_AUTH_TOKEN'
client = Client(account_sid, auth_token)

# Send test message to South Korea
message = client.messages.create(
    to='+821012345678',  # Korean mobile number
    from_='+14155551234',  # Your Twilio number
    body='테스트 메시지입니다.'  # "This is a test message" in Korean
)

print(f"Message SID: {message.sid}")
print(f"Status: {message.status}")

• Analyze Volume-Based Pricing: Understand the tiered pricing structures and volume discounts each provider offers to optimize costs based on your projected usage.
• Consider Long-Term Scalability: Choose a provider that accommodates your future growth and increasing message volumes.
• Assess Technical Support Quality: Reliable technical support is crucial for troubleshooting issues and ensuring smooth operation. Support comparison: Twilio offers 24/7 phone/email support for paid accounts with typical response times of 4–8 hours for non-critical issues. Plivo provides 24/7 email/chat support with 2–6 hour response times. Sinch and Infobip offer dedicated account managers for enterprise contracts (100,000+ messages/month). Verify support availability in your timezone (KST/UTC+9) and whether Korean-language support is available.
• Verify Regulatory Compliance: Ensure your chosen provider handles Korean SMS regulations automatically, including message tags, sender ID prefixes, and character encoding.

Learn more about SMS API integration best practices and international SMS pricing strategies to optimize your messaging infrastructure.

Frequently Asked Questions (FAQ)

How much does it cost to send SMS in South Korea?

SMS pricing in South Korea ranges from $0.036 to $0.049 per message for international providers. Twilio charges $0.0494 per SMS, Plivo charges $0.03625, Sinch charges $0.0431, and Infobip charges $0.0357507. Actual costs vary based on message volume, routing method, and carrier agreements.

What are the SMS regulations in South Korea?

South Korea requires numeric sender IDs (prefixed with 009 or 006), automatic message tags ([Web 발신] or [국제발신]), EUC-KR character encoding, and explicit consent for marketing messages under PIPA. Adult and gambling content is strictly prohibited.

Which carriers operate in South Korea?

South Korea has three major mobile carriers: SK Telecom (48.4% market share), KT Corporation (28.5%), and LG U+ (23.1%). These three carriers control the entire South Korean mobile telecommunications market.

Can I use alphanumeric sender IDs in South Korea?

No, alphanumeric sender IDs are not supported in South Korea. Only numeric sender IDs are allowed, and international long codes are automatically prefixed with 009 or 006 by Korean mobile operators.

What is the best SMS API for South Korea?

The best SMS API for South Korea depends on your specific needs. Infobip offers the lowest per-message rate ($0.0357507), Plivo provides balance of cost and features, Sinch excels in regional expertise and delivery rates, while Twilio offers the most comprehensive documentation and enterprise features.

Do I need consent to send SMS in South Korea?

Yes, explicit written or electronic consent is required before sending marketing SMS messages in South Korea under the Personal Information Protection Act (PIPA). Consent records must be maintained for at least 3 years.

What happens if my SMS fails to deliver in South Korea?

Common delivery failure causes include: (1) Invalid phone number format (ensure +82 country code and valid mobile prefix), (2) EUC-KR encoding issues (non-Korean characters may fail), (3) Prohibited content detected by carrier filters, (4) Landline number (SMS to landlines not supported), (5) Recipient opted out or number on Do-Not-Send Registry. Check error codes from your provider: Twilio error 21614 indicates landline destination; error 30007 indicates carrier filtering. Most providers charge $0.001 per failed message.

How do I handle opt-out requests in South Korea?

Process opt-out requests within 24 hours as legally required. Standard Korean opt-out keywords include 수신거부 ("refuse receipt") and 그만 ("stop"). Implement automated opt-out handling in your application, maintain a centralized suppression list, send confirmation messages acknowledging opt-out status, and check the national Do-Not-Send Registry monthly.

What is the difference between SMS and RCS in South Korea?

SMS (Short Message Service) delivers text messages up to 140 bytes, while RCS (Rich Communication Services) supports rich media, read receipts, typing indicators, and verified Brand Profiles. RCS launched on iPhone in September 2024 across all three major Korean carriers. Learn more about RCS messaging for business.

The Future of Business SMS and RCS in South Korea

While OTT apps like KakaoTalk dominate personal communication, SMS remains vital for businesses in South Korea. Providers continuously adapt to the evolving landscape by offering more competitive pricing, enhanced API features, improved delivery reliability, and expanded integration capabilities.

RCS adoption in South Korea: Rich Communication Services (RCS) launched on iPhone in September 2024 across all three major carriers (SK Telecom, KT, LG U+), supporting iPhone 11+ with latest iOS. RCS enables group messaging with up to 100 participants, read receipts, typing indicators, high-quality media sharing (images/video up to 5 MB without data charges per carrier policy), and verified Brand Profiles for business messaging. Enterprises can leverage RCS Business Messaging for transactional updates (boarding passes, payment confirmations, fraud alerts) with richer layouts and suggested actions. While KakaoTalk retains dominant personal messaging share, RCS provides a standards-based alternative with SIM-based reach and operator-verified sender identity – complementing rather than replacing SMS for critical business communications.

Understand the market dynamics and choose the right provider to leverage SMS for effective communication and enhanced customer engagement in South Korea's telecommunications landscape.