The telephone area code for the entire United States territory of Guam is 671. Since Guam is part of the North American Numbering Plan (NANP), calling a phone number with the Guam area code is treated the same as making a domestic long-distance call within the U.S. and is often subject to domestic calling rates, not international rates.
This article provides essential details about the 671 area code, including the dialing procedure from the mainland U.S., the history of the code, and a list of the major municipalities it covers.
Key Details About the 671 Area Code
Area code 671 is unique in that it is the sole area code for an entire U.S. territory located in the Western Pacific Ocean.
| Detail | Information |
| Area Code (NPA) | 671 |
| Location | Guam (Unincorporated Territory of the U.S.) |
| Time Zone | Chamorro Standard Time (ChST, UTC+10) |
| Dialing Requirement | 10-digit dialing (Area Code + 7-digit number) is mandatory. |
| Major Cities Covered | Dededo, Hagåtña, Tamuning, Yigo, Mangilao |
| Governing System | North American Numbering Plan (NANP) |
Guam’s Unique Calling Status
Guam was added to the NANP in 1997. Prior to this, calling Guam from the mainland U.S. required dialing an international code (011-671), resulting in expensive international long-distance rates. The change to area code 671 made calls between the U.S. and Guam domestic for FCC regulation purposes, significantly reducing costs for many callers.
How to Call a Guam Phone Number from the U.S.
Because Guam is part of the NANP, the dialing format from the United States (or Canada) is straightforward. You do not need to dial the international exit code (011).
Dialing Format for Calling Guam
To place a call from anywhere in the U.S. to Guam, follow this 10-digit dialing sequence:
Example: To call a number in Guam, you would dial 1-671-XXX-XXXX.
Dialing Within Guam
Since October 2021, 10-digit dialing is mandatory even for calls placed within Guam itself. This change was implemented to accommodate the nationwide assignment of the 988 dialing code for the National Suicide Prevention Lifeline, which otherwise conflicted with local 7-digit exchanges.
Time Zone Consideration
Guam observes Chamorro Standard Time (ChST), which is 10 hours ahead of Coordinated Universal Time (UTC+10). Before calling, be sure to check the local time in Guam to avoid calling late at night. For reference, when it is noon Eastern Time (ET) on the U.S. mainland, it is 2:00 AM the following day in Guam.
Major Areas Covered by the 671 Area Code
The 671 area code covers the entire island of Guam, which is divided into various municipalities (villages).
| City/Municipality | Primary Purpose or Prefix Context |
| Dededo | Largest municipality by population. |
| Hagåtña (Agana) | Capital city of Guam. |
| Tamuning | Major commercial and tourism center. |
| Yigo | Northern region, high population density. |
| Mangilao | Location of the University of Guam. |
| U.S. Military Prefixes | Several prefixes, often starting with 3XX, are assigned specifically for military bases. |
| Southern Villages | Includes Agat, Santa Rita, Merizo, and Inarajan. |
Frequently Asked Questions (FAQ)
Is a call to the 671 area code considered an international call?
No. For U.S. landline and major mobile carrier plans, calls to the 671 area code (Guam) are generally considered domestic long-distance calls. This means they are often included in “nationwide calling” plans, just like calls to any U.S. state. Always check your specific mobile plan, as some prepaid or smaller carriers may treat calls to U.S. territories differently.
What is the country code for Guam?
Since Guam is integrated into the NANP, its effective country calling code is +1 (the same as the U.S., Canada, and other Caribbean countries). The full dialing sequence from an international location is typically +1-671 followed by the 7-digit local number.
Is the 671 area code associated with any known scams?
No. Unlike some other area codes from U.S. territories or the Caribbean (which can sometimes be used in neighboring scam operations), the 671 area code for Guam is not widely flagged as a scam-prone code. Any scam call you receive from 671 is likely a standard scammer using a randomly acquired U.S. number, not an area code-specific threat.
Conclusion
The Guam area code is unequivocally 671. Its inclusion in the North American Numbering Plan makes communicating with this crucial U.S. territory in the Pacific relatively simple and affordable for U.S. callers.
When placing a call, simply dial 1-671-XXX-XXXX. Always confirm the 10-hour time difference (ChST) before dialing to ensure you connect at an appropriate time.
