Area code 670: Northern Mariana Islands
What is area code 670?
Area code 670 is a US territory area code for the Northern Mariana Islands, on Chamorro Standard Time. It has 35 prefixes in service across 3 rate centers, the largest being Saipan, Tinian and Rota. NANPA lists no overlay code for it. Local calls there take 7 digits. The code never shows a line is in service.
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See the phone add-onArea code 670 facts
| Location | Northern Mariana Islands, United States |
|---|---|
| Time zone | Chamorro Standard Time |
| Overlays | None |
| In service since | July 1, 1997 |
| Local calls | 7 digits; toll calls 1 + 10 digits |
| Carrier | Not shown. An area code is where a number was issued; numbers port between carriers. Check line type |
In short: 670 is Northern Mariana Islands (Chamorro 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 670
Pacific/Saipan
Prefixes in service
35 of 792 possible
3 rate centers
Which cities and towns use area code 670?
NANPA records each prefix against a rate center, the local billing area a number belongs to, usually named after its main town. These are the 670 rate centers with the most prefixes in service.
| Rate center | Prefixes |
|---|---|
| Saipan | 31 |
| Tinian | 2 |
| Rota | 2 |
Source: NANPA central office code assignments, file dated 10/17/2026. Each prefix holds up to 10,000 numbers.
How do I dial a 670 number?
NANPA's dialling plan for 670: local calls inside the code take 7 digits, toll calls 1 + 10 digits. From another area code, dial 1 first. From abroad, use +1. The examples use 555-0147, from a range reserved for fictional numbers.
| Local call inside 670 | 555-0147 |
|---|---|
| From another US or Canadian area code | 1-670-555-0147 |
| From outside North America | +1 670 555 0147 |
| E.164, for CRMs and SMS tools | +16705550147 |
When did area code 670 start?
Area code 670 went into service on July 1, 1997. It has no overlay, so every number in its area still starts with it.
Tools for 670 numbers
- Bulk phone number validator
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- Area code time zone
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- NPA-NXX lookup
Rate center and state for one prefix, a level below the area code.
- TCPA calling hours checker
Whether it's inside the federal 8 a.m. to 9 p.m. calling window there now.
Next step
A 670 number tells you where it was issued, not what it is now.
Mobiles, landlines and VoIP lines share area codes, and numbers move between carriers. A live line-type and carrier lookup on every number in your list says which is which, and that decides which calling and texting rules apply. It's in the phone add-on.
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Area code 670 questions
- What state or territory is area code 670?
- Area code 670 is in the Northern Mariana Islands, United States. Its largest rate centers by number of prefixes are Saipan, Tinian and Rota.
- What time zone is area code 670 in?
- Chamorro Standard Time.
- Does area code 670 have an overlay?
- Not as of NANPA's file dated 10/16/2026. Every number in its area uses 670.
- When did area code 670 start?
- Area code 670 went into service on July 1, 1997.
- Is a 670 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.
- How many phone numbers does area code 670 have?
- 35 of its 792 possible prefixes are in service, and each prefix holds up to 10,000 numbers. That counts prefixes assigned to carriers, not numbers in use.
- Does a valid format mean a 670 number is in service?
- No. A format check only says the digits fit the North American Numbering Plan and that 670 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 670 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
670 is the only area code in Northern Mariana Islands. 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. Prefixes and rate centers: NANPA central office code assignments, 10/17/2026. Time zones mapped to the IANA time zone database. By the SimpleVerifier Team; how we build these pages.