Complete Guide to SMS Messaging in Netherlands Antilles: Curaçao, Sint Maarten & Caribbean Netherlands (2025)

Netherlands Antilles SMS Market Overview: Compliance, Features & API Integration

Important Note: The Netherlands Antilles dissolved on October 10, 2010 (effective 00:00 UTC-4). This guide covers SMS messaging, compliance requirements, and API integration for the former Netherlands Antilles territories, which now comprise:

• Curaçao (ISO: CW, MCC: 362, +599)
• Sint Maarten (ISO: SX, MCC: 362, +1-721) – joined North American Numbering Plan in 2011
• Caribbean Netherlands – Bonaire, Sint Eustatius, and Saba (ISO: BQ, MCC: 362, +599)
• Aruba (ISO: AW, MCC: 363, +297) – separate country since 1986

Send transactional SMS for 2FA, marketing campaigns, or business notifications to Curaçao, Sint Maarten, or other Caribbean territories using this guide. Learn SMS compliance, phone number formats, carrier requirements, and API integration for successful message delivery.

Market Context: SMS remains the primary channel for business communications across Curaçao, Sint Maarten, and Caribbean Netherlands, particularly for authentication, two-factor verification, and transactional alerts. Each territory maintains distinct regulations, phone number formats (+599, +1-721, +297), and compliance requirements. Master these differences—from data protection laws to alphanumeric sender ID rules—to ensure reliable delivery and regulatory compliance.

What SMS Features Are Supported in Netherlands Antilles Territories?

SMS capabilities in these territories align with Caribbean and international standards, supporting basic messaging features while maintaining strict compliance requirements.

Is Two-Way SMS Supported in Curaçao and Sint Maarten?

Two-way SMS is not supported in these territories according to current provider specifications. This limitation affects interactive messaging campaigns and automated response systems.

Impact on your messaging:

• You cannot receive replies to your SMS messages
• Automated response systems and chatbots won't work via SMS
• Use alternative channels (email, web forms, messaging apps) for two-way communication

How Do Concatenated Messages Work in Netherlands Antilles?

Support: Yes, standard SMS protocols support concatenated messaging.

Message length rules:

• GSM-7 encoding: 160 characters per segment
• Unicode (UCS-2): 70 characters per segment
• Multi-segment messages: 153 characters (GSM-7) or 67 characters (Unicode) per segment

Encoding considerations: Both GSM-7 and UCS-2 (Unicode) encodings work. Use GSM-7 for Latin alphabet messages to maximize character count and reduce costs.

Can You Send MMS to Netherlands Antilles?

Your MMS messages automatically convert to SMS with an embedded URL link. This conversion ensures delivery while providing a way to share multimedia content through linked resources.

How it works:

• Send an MMS message with image, video, or audio
• Recipients receive an SMS with a URL
• They click the URL to view multimedia content in their browser

Phone Number Compatibility and Portability

Is Number Portability Available in Caribbean Territories?

Curaçao, Sint Maarten, and Aruba: Number portability services allow users to keep their phone numbers when switching carriers. This doesn't impact SMS delivery or routing – your messages reach recipients regardless of their current carrier.

Caribbean Netherlands (Bonaire, Saba, Sint Eustatius): Number portability is not supported. The Telecommunications Regulatory Authority (TRA) manages phone number allocation. Subscribers must obtain new numbers when switching providers.

Can You Send SMS to Landlines in Netherlands Antilles?

You cannot send SMS to landline numbers. Attempts to message landline numbers result in a 400 response with error code 21614. The message won't be delivered or charged to your account.

SMS Compliance and Regulatory Requirements for Netherlands Antilles

The constituent countries of the former Netherlands Antilles each maintain their own telecommunications and data protection regulations. While they follow European-style principles as part of the Kingdom of the Netherlands framework, GDPR does not directly apply to these Caribbean territories.

Applicable Regulations by Territory:

• Curaçao: National Ordinance on the Protection of Personal Data (Landsverordening bescherming persoonsgegevens) – enacted October 1, 2013. Enforced by the Personal Data Protection Board (College Bescherming Persoonsgegevens), established January 28, 2022, chaired by Caroline Fiévez. Violations may result in fines up to 10,000 Netherlands Antillean guilders (NAf). The Board has authority to investigate data processing activities on its own initiative or upon request. The telecommunications regulatory body rebranded as Regulatory Authority of Curaçao (RAC) in mid-2024, transitioning from Bureau Telecommunicatie en Post (BT&P). Official site: rac.cw.
• Sint Maarten: National Ordinance Personal Data Protection (Landsverordening bescherming persoonsgegevens) – enacted 2010. Critical oversight gap: The Personal Data Protection Supervisory Committee mandated by Article 42 has never been established since the law's enactment. As confirmed by the General Audit Chamber's 2025 performance audit, Sint Maarten has no functioning oversight mechanism to enforce data protection laws or protect citizens' privacy rights, despite having legislation in place for 15 years. Citizens cannot rely on legally established oversight. Compare this to the BES islands (Caribbean Netherlands), which established a supervisory committee in 2014.
• Caribbean Netherlands: Dutch Telecommunications Act applies with modifications. The Telecommunications Regulatory Authority (TRA) manages numbering allocation and adheres to ITU-T recommendations E.123 and E.164. Mobile prefixes: Bonaire (7XX), Sint Eustatius (318), Saba (416), all using +599 country code.
• Aruba: National Ordinance Person Registration (Landsverordening persoonsregistratie, AB 2011 no. 37) – enacted May 19, 2011. Overseen by the Minister of Justice and Security; no dedicated data protection authority.

Key Regulatory Principles:

• Explicit consent required for marketing communications
• Right to access, rectification, and erasure of personal data
• Data breach notification requirements
• Cross-border data transfer restrictions
• Telecommunications licensing and compliance

What Consent Requirements Apply to SMS Marketing?

Explicit Consent Requirements:

• Obtain written or electronic opt-in before sending marketing messages
• Maintain consent records and make them easily accessible
• Clearly state the purpose of messaging during opt-in
• Implement double opt-in for marketing campaigns (recommended)
• Separate consent for different message types (transactional vs. marketing)

Best Practices for Documentation:

• Store timestamp, IP address, and source of consent
• Maintain detailed records of opt-in methods
• Conduct regular audits of consent database
• Enable easy access to consent history
• Document consent withdrawal requests with timestamps

Territory-Specific Considerations:

• Sint Maarten: Due to the absence of a functioning oversight authority since 2010, businesses must maintain exceptionally rigorous self-compliance practices. Without regulatory enforcement, documented consent procedures become your primary legal protection.
• Curaçao: The Personal Data Protection Board (established 2022) actively investigates data processing. Ensure consent records are immediately accessible for potential Board inquiries.
• Caribbean Netherlands: Follow Dutch data protection principles. The TRA focuses on telecommunications compliance while data protection aligns with Kingdom standards.

How to Implement HELP/STOP Commands

You must support STOP, HELP, and similar opt-out commands:

• Recognize commands in English, Dutch, and Papiamento where applicable
• Support standard keywords: STOP, STOPPEN, HELP, INFO, ARRET (for French-speaking users)
• Send automated response confirming opt-out status immediately
• Process opt-out requests within 24 hours maximum

Do Not Call Registry Requirements

No centralized Do Not Call registry exists for these territories. You must:

• Maintain your own suppression lists per territory
• Honor opt-out requests within 24 hours
• Implement automated STOP command processing
• Regularly clean and update contact databases
• Respect cross-territory opt-out preferences

What Time Zone Should You Use for SMS Scheduling?

Time Zone: Atlantic Standard Time (AST, UTC-4) – no daylight saving time observed year-round

• Recommended sending hours: 8:00 AM to 8:00 PM AST (12:00 PM to 12:00 AM UTC)
• Avoid sending during local holidays and religious observances
• Consider Carnival season (January–March) for adjusted scheduling
• Emergency and transactional messages (2FA, alerts) exempt from time restrictions

Local Holidays to Observe:

• New Year's Day (January 1)
• Carnival Monday (varies, February–March)
• Good Friday and Easter Monday (varies)
• King's Day (April 27)
• Labour Day (May 1)
• Ascension Day (varies, May)
• Christmas (December 25–26)

Phone Number Formats and Sender IDs for Netherlands Antilles

Understanding the correct phone number formats for each territory is essential for successful SMS delivery in the Netherlands Antilles region.

Phone Number Format by Territory:

• Curaçao: +599 9XX XXXX (7 digits after country code). Mobile numbers use +599 95X XXXX format.
• Sint Maarten: +1 721 XXX XXXX (10 digits total, North American Numbering Plan format)
• Bonaire: +599 7XX XXXX
• Sint Eustatius: +599 318 XXXX
• Saba: +599 416 XXXX
• Aruba: +297 XXX XXXX

Major Mobile Carriers by Island:

• Curaçao: Flow (formerly UTS, 45% market share), Digicel (55% market share). Flow offers superior 4G/LTE coverage in Willemstad and across the island (launched 2015). Digicel launched 4G/LTE on Band 3 (1800 MHz) in 2017. No 5G available as of 2025.
• Sint Maarten: TelEm (TelCell), the sole local telecommunications operator using +1-721 (North American Numbering Plan). Operates unified network across Sint Maarten, Saba, and Sint Eustatius with no roaming fees between these territories.
• Bonaire: Flow (Chippie), Digicel (75% market share). Both offer 4G/LTE coverage. Flow data plans work across Sint Maarten, Saba, Sint Eustatius, and St. Kitts & Nevis at no extra cost. Digicel offers roaming across ABC islands (Aruba, Curaçao, Bonaire) without surcharges.
• Saba: TelEm (TelCell), unified with Sint Maarten network
• Sint Eustatius: TelEm (TelCell), unified with Sint Maarten network

Can You Use Alphanumeric Sender IDs in Curaçao and Sint Maarten?

Operator network capability: Supported

Registration requirements: No pre-registration required for most operators

Sender ID preservation: Sender IDs display exactly as you send them

Character limits: 3–11 alphanumeric characters (no spaces)

Best practices: Use consistent, recognizable brand names (e.g., "YourBrand," "ACME-Bank")

Are Long Codes and Short Codes Available?

Long Codes:

• Domestic long codes: Not supported
• International long codes: Available for messaging
• Sender ID preservation: Your original sender ID is maintained
• Provisioning time: Typically 1–2 business days
• Use cases: Transactional messages, alerts, notifications

Short Codes:

• Support: Not currently supported in these territories
• Provisioning time: N/A
• Use cases: N/A

SMS Content Restrictions and Filtering Rules for Netherlands Antilles

Restricted Industries:

• Gambling and betting services
• Adult content
• Cryptocurrency promotions
• Unauthorized financial services

Regulated Industries:

• Banking and finance: Require additional verification
• Healthcare: Messages must maintain privacy standards
• Insurance: Services need clear disclaimers

SMS Content Filtering and Anti-Spam Rules

Known Carrier Rules:

• Use URLs from verified domains only
• Avoid excessive capitalization (looks like spam)
• Limit special characters
• Don't embed images or rich media (use MMS conversion instead)

Anti-Spam Guidelines:

• Avoid repetitive messaging to the same recipients
• Don't use aggressive sales language ("ACT NOW!" "LIMITED TIME!")
• Include clear company identification in every message
• Maintain consistent sender IDs across campaigns

Best Practices for Sending SMS to Netherlands Antilles Territories

Messaging Strategy

• Keep messages under 160 characters when possible
• Include a clear, actionable call-to-action
• Use personalization tokens thoughtfully (name, account details)
• Maintain consistent brand voice and sender ID across campaigns
• Provide value in every message – avoid unnecessary communications

Sending Frequency and Timing

• Limit marketing messages to 4–5 per month per recipient
• Transactional messages (2FA, alerts) have no frequency limits
• Respect local holidays, weekends, and cultural events
• Space messages at least 24–48 hours apart
• Monitor engagement metrics (open rates, click-through rates) to optimize timing

How to Localize SMS for Caribbean Audiences

Language Support:

• Dutch: Official language in all territories
• English: Widely spoken, especially in Sint Maarten
• Papiamento: Spoken in Curaçao, Bonaire, and Aruba
• Spanish: Understood by many residents

Cultural Considerations:

• Use appropriate greetings ("Bon dia" in Papiamento, "Goedemorgen" in Dutch)
• Use local date formats: DD-MM-YYYY
• Use 24-hour time format or clearly specify AM/PM
• Respect cultural and religious diversity
• Consider multilingual campaigns for broader reach

Opt-Out Management

• Process opt-outs immediately (within minutes, not hours)
• Confirm opt-out status via SMS: "You've been unsubscribed from [Brand] messages. Text HELP for assistance."
• Maintain opt-out lists across all campaigns
• Clean your database regularly to remove invalid numbers

Testing and Monitoring

• Test across major local carriers in each territory
• Monitor delivery rates and identify problem areas
• Track engagement metrics (delivery rate, click-through rate, conversion rate)
• Generate regular performance reports
• Set up alerts for delivery rate drops below threshold (e.g., <95%)

SMS API Integration for Netherlands Antilles: Twilio, Sinch, MessageBird & Plivo

Twilio SMS API Integration

Twilio provides a robust SMS API with comprehensive support for the Netherlands Antilles. Integration requires your Account SID and Auth Token from the Twilio Console.

import { Twilio } from 'twilio';

// Initialize Twilio client
const client = new Twilio(
  process.env.TWILIO_ACCOUNT_SID,
  process.env.TWILIO_AUTH_TOKEN
);

async function sendSMS() {
  try {
    // Send message with proper formatting for Netherlands Antilles
    const message = await client.messages.create({
      body: 'Your message here', // Keep under 160 chars for single SMS
      from: 'YourSenderID', // Alphanumeric sender ID or Twilio number
      to: '+599XXXXXXXX' // Netherlands Antilles number format
    });
    
    console.log(`Message sent successfully: ${message.sid}`);
  } catch (error) {
    console.error('Error sending message:', error);
  }
}

Sinch SMS API Integration

Sinch offers direct carrier connections for reliable message delivery in the Netherlands Antilles.

import { SinchClient } from '@sinch/sdk-core';

// Initialize Sinch client
const sinchClient = new SinchClient({
  servicePlanId: process.env.SINCH_SERVICE_PLAN_ID,
  apiToken: process.env.SINCH_API_TOKEN,
  region: 'eu'  // Use EU region for Netherlands Antilles
});

async function sendSMS() {
  try {
    const response = await sinchClient.sms.batches.create({
      from: 'YourSenderID',
      to: ['+599XXXXXXXX'],
      body: 'Your message here',
      delivery_report: 'summary' // Enable delivery reporting
    });
    
    console.log('Batch ID:', response.id);
  } catch (error) {
    console.error('Sending failed:', error);
  }
}

MessageBird SMS API Integration

MessageBird provides reliable SMS delivery with detailed delivery reporting.

import messagebird from 'messagebird';

// Initialize MessageBird client
const mbClient = messagebird(process.env.MESSAGEBIRD_API_KEY);

// Function to send SMS
function sendSMS() {
  const params = {
    originator: 'YourBrand',
    recipients: ['+599XXXXXXXX'],
    body: 'Your message here',
    reportUrl: 'https://your-callback-url.com/delivery-reports'
  };

  mbClient.messages.create(params, (err, response) => {
    if (err) {
      console.error('Error:', err);
      return;
    }
    console.log('Message sent:', response.id);
  });
}

Plivo SMS API Integration

Plivo offers high-throughput SMS capabilities for the Netherlands Antilles.

import plivo from 'plivo';

// Initialize Plivo client
const plivoClient = new plivo.Client(
  process.env.PLIVO_AUTH_ID,
  process.env.PLIVO_AUTH_TOKEN
);

async function sendSMS() {
  try {
    const message = await plivoClient.messages.create({
      src: 'YourSenderID', // Your sender ID
      dst: '+599XXXXXXXX', // Destination number
      text: 'Your message here',
      url: 'https://your-callback-url.com/delivery-status'
    });
    
    console.log('Message UUID:', message.messageUuid);
  } catch (error) {
    console.error('Failed to send:', error);
  }
}

API Rate Limits and Throughput

• Default rate limit: 100 messages per second
• Batch processing: Recommended for large volumes
• Retry logic: Implement exponential backoff
• Peak times: Queue messages and schedule across off-peak hours

Throughput Management Strategies:

• Implement a message queuing system (RabbitMQ, AWS SQS)
• Use batch APIs for bulk sending (500+ messages)
• Monitor delivery rates and adjust send speed accordingly
• Schedule high-volume campaigns across off-peak hours

Error Handling and Delivery Reporting

Common Error Scenarios:

• Invalid phone numbers: Format doesn't match territory standards
• Network timeouts: Carrier or API connectivity issues
• Rate limit exceeded: Too many messages sent too quickly
• Invalid sender ID: Sender ID violates character limits or content rules

Best Practices:

• Implement comprehensive error logging with timestamps and context
• Monitor delivery rates in real-time
• Set up automated alerts for delivery failures >5%
• Maintain error response documentation for your team
• Implement retry queues for transient failures

Frequently Asked Questions About SMS in Netherlands Antilles

Can I send SMS to Netherlands Antilles using the AN country code?

No, the AN country code is deprecated since the Netherlands Antilles dissolved in October 2010. Use the specific country codes for each territory: +599 (Curaçao, Caribbean Netherlands), +1-721 (Sint Maarten), or +297 (Aruba).

Does GDPR apply to SMS marketing in Curaçao and Sint Maarten?

No, GDPR does not directly apply to these Caribbean territories. Each territory has its own data protection laws: Curaçao has the Landsverordening bescherming persoonsgegevens (2013), Sint Maarten has the National Ordinance Personal Data Protection (2010), and Aruba has the National Ordinance Person Registration (2011). All require explicit consent for marketing communications.

What's the best SMS API provider for Netherlands Antilles?

Popular SMS API providers with Caribbean coverage include Twilio, Sinch, MessageBird, and Plivo. All support alphanumeric sender IDs and provide delivery reporting. Choose based on your specific needs for throughput, pricing, and regional support.

How do I format phone numbers for Sint Maarten vs Curaçao?

Sint Maarten uses the North American Numbering Plan format: +1 721 XXX XXXX (10 digits total). Curaçao uses: +599 9XXX XXXX (7 digits after country code). Always use E.164 format with the plus sign and country code for international SMS delivery.

Is two-way SMS supported in Netherlands Antilles territories?

No, two-way SMS is not currently supported in Curaçao, Sint Maarten, Caribbean Netherlands, or Aruba. If you need interactive messaging, use alternative channels like email, web forms, or messaging apps.

What are the SMS character limits for these territories?

Standard SMS limits apply: 160 characters per segment for GSM-7 encoding, or 70 characters for Unicode (UCS-2). Multi-segment messages use 153 characters (GSM-7) or 67 characters (Unicode) per segment due to concatenation headers.

Do I need to register my sender ID for Curaçao?

No, alphanumeric sender IDs do not require pre-registration for most operators in Netherlands Antilles territories. Your sender ID (3–11 alphanumeric characters) will display exactly as you send it. Use consistent, recognizable brand names.

What time should I send marketing SMS to avoid complaints?

Send between 8:00 AM to 8:00 PM Atlantic Standard Time (AST, UTC-4). Avoid local holidays like Carnival, King's Day, and Christmas. Transactional messages (2FA, alerts) are exempt from time restrictions.

Can I send SMS to mobile numbers that switched carriers?

Yes, in Curaçao, Sint Maarten, and Aruba where number portability is available. However, the Caribbean Netherlands (Bonaire, Saba, Sint Eustatius) does not currently support number portability.

What happens if I send SMS to a landline number?

The message will fail with a 400 error (error code 21614). You will not be charged for the failed message. Always validate that recipients have mobile numbers before sending SMS.

Recap and Additional Resources

Key Takeaways

1. Territory-Specific Considerations:

   • The Netherlands Antilles dissolved October 10, 2010 – now five separate territories
   • Each territory has distinct dialing codes and regulations
   • Verify recipient phone number format per territory

2. Compliance Focus:

   • Obtain explicit consent before sending marketing messages
   • Honor opt-out requests within 24 hours
   • Maintain proper documentation and consent records
   • Follow territory-specific data protection laws (not GDPR)

3. Technical Considerations:

   • Use appropriate sender IDs (alphanumeric supported)
   • Implement proper error handling for invalid numbers
   • Monitor delivery rates per territory
   • Account for multiple dialing codes (+599, +1-721, +297)

4. Best Practices:

   • Respect Atlantic Standard Time (AST, UTC-4)
   • Maintain clean, segmented contact lists by territory
   • Support multilingual content (Dutch, English, Papiamento)
   • Conduct regular testing and monitoring

Next Steps

1. Technical Setup:

   • Choose an SMS API provider with Caribbean coverage (Twilio, Sinch, MessageBird, Plivo)
   • Implement phone number validation for multiple formats (+599, +1-721, +297)
   • Set up monitoring systems with territory-specific tracking
   • Configure webhook endpoints for delivery reports

2. Compliance:

   • Review territory-specific data protection regulations (see links below)
   • Establish a consent management system with audit trails
   • Document your compliance procedures per territory
   • Implement automated opt-out processing

3. Testing:

   • Verify delivery rates across all five territories
   • Test opt-out functionality in multiple languages
   • Monitor message performance and engagement
   • Validate phone number formats and routing

Additional Resources:

• Regulatory Authority of Curaçao (RAC) – Telecommunications and data protection regulator (formerly Bureau Telecommunicatie en Post)
• Government of Sint Maarten – Telecommunications
• Aruba Telecommunications Authority
• ITU Caribbean Telecommunications
• CTIA Messaging Principles and Best Practices