The 671 area code is a valid and official telephone area code within the North American Numbering Plan (NANP), exclusively serving the U.S. territory of Guam.
Located in the Western Pacific Ocean, Guam is a critical military and economic hub. While it is physically across the International Date Line from the mainland US, the 671 area code allows callers from the United States and Canada to treat calls to Guam as domestic long-distance calls, not international calls, resulting in significantly lower rates.
This guide provides the full details on the location, time zone, major cities, and current 10-digit dialing rules for the 671 area code.
Where is the 671 Area Code Located?
The 671 area code covers the entire island of Guam, which is the largest and southernmost island in the Mariana Islands archipelago.
| Detail | Information |
| Area Code: | 671 |
| Location: | Guam (Unincorporated Territory of the United States) |
| Country Code: | +1 (Part of the North American Numbering Plan) |
| Largest City: | Dededo |
| Capital City: | Hagåtña |
| Major Cities Covered: | Tamuning, Yigo, Barrigada, Mongmong-Toto-Maite |
The Time Zone for Area Code 671
Due to its distant location in the Pacific, Guam has a significant time difference from the US mainland.
- Time Zone Name: Chamorro Standard Time (ChST)
- Time Offset: UTC/GMT +10 hours
- Daylight Saving Time: Guam does not observe Daylight Saving Time.
This means Guam is consistently 15 hours ahead of U.S. Eastern Standard Time (EST) and 18 hours ahead of U.S. Pacific Standard Time (PST). When it is noon in New York, it is 3:00 AM the next day in Guam.
Dialing Rules for the 671 Area Code
Since Guam is integrated into the NANP, all calls to and from the territory follow standard North American 10-digit dialing rules.
Calling Guam from the US or Canada
To call any number in the 671 area code, you must dial the long-distance prefix (1), followed by the area code and the 7-digit local number.
Example (Calling Guam from California):
Local Dialing Requirement: 10-Digit Dialing
Prior to 2021, local calls within Guam only required 7 digits. However, due to the nationwide assignment of “988” as the National Suicide Prevention Lifeline, all calls within the 671 area code are now required to use 10-digit dialing (671 + 7-digit number), even when calling a neighbor.
(Required for all local calls within Guam)
Call Costs and Scams
A key benefit of Guam’s inclusion in the NANP is cost savings for callers in the US and Canada.
Calling Costs
- From US/Canada: Calls to the 671 area code are generally billed at domestic long-distance rates or included in your standard unlimited calling package. They are not billed at expensive international rates by US carriers.
- To Other Countries: Calls made from Guam to countries outside the NANP (e.g., Japan, Philippines) are still considered international and will incur international rates.
Scam Alert Status
The 671 area code is not typically associated with the high-cost international “one-ring” scams, which usually exploit non-NANP country codes (like +237 or +670). However, like any North American area code, it can be subject to caller ID spoofing by scammers attempting to make a call look local or domestic. Always be cautious of unsolicited calls asking for personal information or payment.
Frequently Asked Questions (FAQ)
Is 671 a US area code?
Yes. The 671 area code belongs to the U.S. territory of Guam and is fully integrated into the North American Numbering Plan, alongside US states and Canadian provinces.
How do I dial a local Guam number if I am on the island?
If you are physically on the island of Guam, you must dial the full 10-digit number (671 + 7-digit local number) for all local calls. This change was implemented to accommodate the new 988 National Suicide Prevention Lifeline access number.
What is the country code for Guam?
Technically, the country code for Guam, as part of the NANP, is +1. The 671 is the area code that follows it. The full international format for a Guam number is therefore: +1 (671) XXX-XXXX.
