Guam area codes
Guam uses 1 area code. Its code 671 has been in service since 1997. It has 95 of its 786 possible number blocks allocated, 12.1% 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 1 rate center in 671, and local calls take all ten digits.
The Guam area code
| Code | In service | Blocks used | Largest holder | Complaints | Shares area with |
|---|---|---|---|---|---|
| 671 | 1997 | 95/786 | 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 Guam’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: 95 blocks, each with the holder NANPA recorded for it. Percentages are measured, not estimated.
| Holder | Blocks | Share of Guam | Largest in |
|---|---|---|---|
| Other CLEC / VoIP | 95 | 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
Guam is in Chamorro time. NANPA records this code by UTC offset (+10), not by a continental zone name.
Frequently asked about Guam area codes
How many area codes does Guam have?
1 in service. That code is 671.
What is the oldest area code in Guam?
671, in service since 1997.
What time zone is Guam in?
Chamorro time. NANPA records this code by UTC offset (+10), not by a continental zone name.
Which carrier holds the most Guam numbers?
No one carrier does. 100.0% of the 95 number blocks assigned across Guam 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.
Do you have to dial 10 digits in Guam?
Yes. The code is in a ten-digit dialing area, so a local call needs the area code too. Dialing seven digits reaches a recording, not a wrong number.
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.