Area code 721: Sint Maarten
What is area code 721?
Area code 721 is an area code for Sint Maarten, which is part of the North American Numbering Plan but not the US or Canada. It is on Atlantic Standard Time. NANPA lists no overlay code for it. Calls to it from the US and Canada are international calls. Local calls there take 7 digits.
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See the phone add-onArea code 721 facts
| Location | Sint Maarten |
|---|---|
| Time zone | Atlantic Standard Time |
| Overlays | None |
| In service since | September 30, 2011 |
| Local calls | 7 digits |
| Carrier | Not shown. An area code is where a number was issued; numbers port between carriers. Check line type |
In short: 721 is Sint Maarten (Atlantic Standard Time). Format checks here are free and run in your browser; the current carrier and line type need a live lookup. Bulk phone number validator · Pro + Phone plan
Local time in area code 721
America/Lower_Princes
Prefixes in service
No public data
Administered by the country's own regulator
How do I dial a 721 number?
NANPA's dialling plan for 721: local calls inside the code take 7 digits. Sint Maarten is a separate country or territory inside the North American Numbering Plan, so a call there from the US or Canada is dialled like a domestic one but billed as international. The examples use 555-0147, from a range reserved for fictional numbers.
| Local call inside 721 | 555-0147 |
|---|---|
| From the US or Canada | 1-721-555-0147 |
| From outside North America | +1 721 555 0147 |
| E.164, for CRMs and SMS tools | +17215550147 |
When did area code 721 start?
Area code 721 went into service on September 30, 2011. It has no overlay, so every number in its area still starts with it.
Tools for 721 numbers
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Next step
A 721 number tells you where it was issued, not what it is now.
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Area code 721 questions
- What country is area code 721?
- Area code 721 is in Sint Maarten.
- What time zone is area code 721 in?
- Atlantic Standard Time.
- Does area code 721 have an overlay?
- Not as of NANPA's file dated 10/16/2026. Every number in its area uses 721.
- When did area code 721 start?
- Area code 721 went into service on September 30, 2011.
- Is a 721 number a cell phone or a landline?
- The area code can't tell you. In the US and Canada mobiles, landlines and VoIP lines share area codes and prefixes, and numbers move between carriers and line types. Only a live line-type lookup answers it for one number.
- Does a valid format mean a 721 number is in service?
- No. A format check only says the digits fit the North American Numbering Plan and that 721 is an assigned code. It cannot tell whether the number is connected, who answers it or which carrier serves it today, because numbers are reassigned and ported. A live carrier lookup reports the current carrier and line type, but even that is not proof someone answers.
- Can I check a list of 721 numbers for free?
- Yes. Paste them in the list tab above or upload a CSV to the bulk phone number validator: format, E.164, country and the numbering-plan line type are free for every row, with no account. Live carrier and line-type lookups come with Pro + Phone at $49.99/mo (5,000 a month).
More area codes
721 is the only area code in Sint Maarten. Browse every area code by state and province on the area code index.
Sources
Location, overlays, in-service date and dialling plan: NANPA NPA database, file dated 10/16/2026. Time zones mapped to the IANA time zone database. By the SimpleVerifier Team; how we build these pages.