Northern Mariana Islands area codes
Northern Mariana Islands uses 1 area code. Its code 670 has been in service since 1997. It has 35 of its 786 possible number blocks allocated, 4.5% of capacity. Across the territory no single national carrier holds the most blocks: 100.0% sits with CLEC and VoIP holders counted together. All of it is Chamorro time. NANPA records this code by UTC offset (+10), not by a continental zone name. NANPA records 3 rate centers in 670.
The Northern Mariana Islands area code
| Code | In service | Blocks used | Largest holder | Complaints | Shares area with |
|---|---|---|---|---|---|
| 670 | 1997 | 35/786 | Other CLEC / VoIP 100% | – | no overlay |
Block share is share of allocated number blocks, not of subscribers. Complaint counts cover 28 Sep – 30 Oct 2026 and reflect spoofed caller IDs as much as real calls.
How full Northern Mariana Islands’s codes are
A code holds at most 786 blocks of 10,000 numbers each. When a code fills up, the administrator does not reclaim numbers – it adds an overlay, and from then on new numbers in the same area come from the new code.
Most room left
Who holds the number blocks
Counted from every assigned block in the territory: 35 blocks, each with the holder NANPA recorded for it. Percentages are measured, not estimated.
| Holder | Blocks | Share of Northern Mariana Islands | Largest in |
|---|---|---|---|
| Other CLEC / VoIP | 35 | 100% | 1 code |
“Other CLEC / VoIP” is not one company: it is every holder outside the national carriers counted together, which is what resellers and app-based numbers look like in the records. This is allocation, not subscribers.
Time zones
Northern Mariana Islands is in Chamorro time. NANPA records this code by UTC offset (+10), not by a continental zone name.
Frequently asked about Northern Mariana Islands area codes
How many area codes does Northern Mariana Islands have?
1 in service. That code is 670.
What is the oldest area code in Northern Mariana Islands?
670, in service since 1997.
What time zone is Northern Mariana Islands in?
Chamorro time. NANPA records this code by UTC offset (+10), not by a continental zone name.
Which carrier holds the most Northern Mariana Islands numbers?
No one carrier does. 100.0% of the 35 number blocks assigned across Northern Mariana Islands are held by CLEC and VoIP providers outside the national carriers – resellers and app-based numbers look like this in the records. This is allocation of blocks by the numbering administrator, not a count of subscribers – people keep their numbers when they switch carriers.
Sources and verification
- NANPA – NPA Database (npa_report.csv), file date 11/01/2026, retrieved Nov 1, 2026
- NANPA – CO Code Assignment Records, All States (utilized), file updated 11/01/2026, retrieved Nov 1, 2026
Figures on this page are counted from those files, not copied from other sites. Spotted an error? Request a correction. How we collect and check: methodology.