The +1721 country code is for Sint Maarten, the southern (Dutch) half of the island of Saint Martin in the northeastern Caribbean. The island is split between two countries: Sint Maarten (a constituent country of the Kingdom of the Netherlands) and Saint-Martin (a French overseas collectivity). They share 37 square miles of land but use entirely different phone systems.
Sint Maarten's roughly 43,000 residents use NANP area code 721. The French side uses +590, the same code as Guadeloupe. This means calling someone five minutes away on the other side of the border is an international call with a completely different country code. It is one of the more confusing telecom setups in the Caribbean.
Quick answer: The country code for Sint Maarten is +1-721 (NANP area code 721). Local numbers are 7 digits. There is no trunk prefix. The French side of the island uses +590, not +1-721.
How to call Sint Maarten: quick reference
Sint Maarten uses NANP area code 721, so calling from the US or Canada follows the same pattern as any other area code. From outside North America, prefix with your international access code plus 1-721.
| Calling from | Dialing format |
|---|---|
| US/Canada mobile | 1-(721)-XXX-XXXX |
| US/Canada landline | 1-(721)-XXX-XXXX |
| UK | 00-1-(721)-XXX-XXXX |
| Netherlands | 00-1-(721)-XXX-XXXX |
| Within Sint Maarten | XXX-XXXX (7 digits) |
| Elsewhere | +1-(721)-XXX-XXXX |
Understanding Sint Maarten phone numbers
All Sint Maarten phone numbers follow the NANP format: (721) XXX-XXXX. The 721 area code covers the entire Dutch side of the island.
Mobile numbers
Mobile numbers are 7 digits. Common mobile prefixes include 520-527, 550-554, and 580-586. A typical mobile number looks like (721) 520-1234.
Landline numbers
Landline numbers also use 7 digits. Prefixes like 542-544 are common in Philipsburg and surrounding areas. A sample landline: (721) 542-5678.
Important: Dutch side only
The 721 area code applies only to the Dutch side (Sint Maarten). If you are trying to reach someone on the French side (Saint-Martin), you need to dial +590 instead. There is no way to tell from a street address alone which phone system someone uses, so always confirm the country code when getting a number from someone on the island.
Mobile carriers in Sint Maarten
Sint Maarten has a small telecom market with a few carriers serving the Dutch side.
TelEm (Sint Maarten Telephone Company)
TelEm is the incumbent carrier, handling most landline connections and offering mobile service. It is government-owned and has been the main provider since the island's telecom infrastructure was first built. TelEm also provides internet and cable TV.
TelCell
TelCell is TelEm's mobile subsidiary and one of the two main mobile networks on the Dutch side. It has decent coverage across Philipsburg, Simpson Bay, and the main populated areas.
UTS/Chippie
UTS (United Telecommunication Services), operating under the Chippie brand, is the other mobile carrier. Originally from Curacao, it operates across several Dutch Caribbean islands. Chippie competes on prepaid pricing and offers 4G coverage on Sint Maarten.
On the French side, the carriers are different entirely (Orange, Dauphin Telecom, SFR Caraibes), and they operate on the +590 network. Your phone will switch networks as you cross the unmarked border, which can cause unexpected roaming charges.
Don't confuse +1721 with nearby codes
The biggest source of confusion with Sint Maarten is not other NANP codes but the French side of the same island.
| Code | Territory | How to tell apart |
|---|---|---|
| +1-721 | Sint Maarten (Dutch side) | This article |
| +590 | Saint-Martin (French side) | Same island, different country code |
| +599 | Curacao / Bonaire / Saba / Sint Eustatius | Other Dutch Caribbean islands (non-NANP) |
| +1-284 | British Virgin Islands | Nearby NANP territory |
People often assume that because Sint Maarten is Dutch, it shares a country code with Curacao or Bonaire (+599). It does not. Sint Maarten joined the NANP and got its own area code (721) when it became a separate constituent country in 2010.
Time zone considerations
Sint Maarten runs on Atlantic Standard Time (AST), which is UTC-4 year-round. No daylight saving time is observed.
| Your location | When it's 10:00 AM in Sint Maarten |
|---|---|
| New York (EST/EDT) | 9:00 AM (winter) / 10:00 AM (summer) |
| Los Angeles (PST/PDT) | 6:00 AM (winter) / 7:00 AM (summer) |
| Amsterdam (CET/CEST) | 3:00 PM (winter) / 4:00 PM (summer) |
| London (GMT/BST) | 2:00 PM (winter) / 3:00 PM (summer) |
The Amsterdam row matters because many Sint Maarten residents have ties to the Netherlands. In winter, Sint Maarten is 5 hours behind Amsterdam. In summer, the gap is 6 hours because the Netherlands moves clocks forward while Sint Maarten stays put.
Communication in Sint Maarten
Business hours
Government offices operate Monday through Friday, roughly 8:00 AM to 4:30 PM AST. Banks close earlier, typically by 3:30 PM. Many tourist-oriented businesses in Philipsburg and Simpson Bay keep longer hours and stay open on weekends during cruise ship season (November through April).
Languages
Dutch is the official language, but English is the most widely spoken language in daily life. You will also hear Spanish and Papiamento, especially among workers from other Caribbean islands. On the French side, the default switches to French. Phone menus and voicemail greetings on the Dutch side are almost always in English.
Network quality
4G LTE is available across the Dutch side from both TelCell and Chippie. Coverage is good in populated areas since the territory is small and flat along the coast. Hurricane Irma in 2017 destroyed much of the island's infrastructure, but the telecom networks have been rebuilt. Occasional outages still happen during hurricane season (June through November).
The Sint Maarten diaspora
Where Sint Maarteners have settled
The largest diaspora communities are in the Netherlands (Amsterdam, Rotterdam, The Hague), the United States (particularly the New York and Miami areas), and other Dutch Caribbean islands like Curacao and Aruba. After Hurricane Irma in 2017, a significant number of residents relocated to the Netherlands, and many have stayed.
Why they call home
Sint Maarten is small enough that most people know each other. Family connections are tight, and regular phone contact is the norm. Tourism drives the economy, so many calls are also business-related: hotel reservations, tour operators, and cruise port logistics.
Carnival (usually in April/May) and Sint Maarten Day (November 11, which marks the island's name day) are peak periods for calls from abroad. The anniversary of Hurricane Irma (September) also generates increased call traffic as people check in on the ongoing rebuilding.
Dialing examples
Calling a mobile in Philipsburg from the US
The mobile number is 520-1234. From a US phone, dial 1-(721)-520-1234. From a US mobile, you can also enter +1-721-520-1234.
Calling a hotel in Simpson Bay from the Netherlands
The hotel landline is 544-5678. From the Netherlands, dial 00-1-721-544-5678. From a Dutch mobile, use +1-721-544-5678.
Calling the French side from the Dutch side
You are in Philipsburg and want to call a restaurant in Marigot (French side). The French number is 0590 29-1234. From your +1-721 phone, dial 00-590-590-29-1234 (international call to +590). This is billed as an international call even though Marigot is a 15-minute drive away.
Local call within Sint Maarten
Calling another +1-721 number from within the Dutch side, just dial the 7-digit number: 542-9876.
Common mistakes to avoid
Using +590 for the Dutch side
The most common mistake. If someone says they are in "Saint Martin" or "Sint Maarten," ask which side. The Dutch side is +1-721. The French side is +590. Using the wrong code will either fail or connect you to someone on the other half of the island.
Assuming it's a domestic US call
Like other Caribbean NANP territories, Sint Maarten uses +1 but is not part of domestic US/Canada calling. Your carrier bills it as international. Using a VoIP service with per-minute rates avoids the surprise.
Expecting +599 because it's Dutch
Curacao, Bonaire, Saba, and Sint Eustatius use +599. Sint Maarten does not. When it became a separate constituent country in 2010, it got its own NANP area code (721) instead of staying under +599.
Roaming surprises on the border
If you are physically on the island with a roaming phone, your device may switch between Dutch-side and French-side cell towers as you move around, especially near the border. This can change which network you are on without warning, affecting both incoming and outgoing call routing and roaming charges.
Prefer calling over WiFi? See our guide to the best apps for WiFi calling.
Frequently asked questions (FAQ)
What country has the +1721 country code?
The +1721 country code is for Sint Maarten, the Dutch side of the island of Saint Martin in the Caribbean. The French side uses +590.
How do I call Sint Maarten from the US?
Dial 1-(721) followed by the 7-digit local number. From a US mobile, you can also dial +1-721-XXX-XXXX. The call will bill as international despite the +1 prefix.
What is the difference between +1721 and +590 on the same island?
+1721 is the Dutch side (Sint Maarten) and +590 is the French side (Saint-Martin). They share the island but have completely separate phone networks, country codes, and billing.
Is calling Sint Maarten from the US a domestic call?
No. Even though Sint Maarten uses +1 like the US and Canada (NANP area code 721), calls are billed as international. Check your plan or use a VoIP service with transparent per-minute rates.
Can I use my US phone number on both sides of the island?
If you are physically on the island, your US phone may roam on either side. But calling a +1-721 number (Dutch side) and a +590 number (French side) are different international calls with different rates, even though the two sides are minutes apart.
Looking for the other side of the island? See our guide to Saint-Martin / Guadeloupe (+590). Also check out British Virgin Islands (+1284) or browse all country codes.