Area Code 671 – Hagåtña & Territory Area

Overview of Area Code 671

Area code 671 is the sole telephony area code serving the United States territory of Guam, a Pacific island strategically located in the Western Pacific Ocean. Administered under the North American Numbering Plan (NANP), Guam is integrated into the global telecommunications network with the country calling code +1, followed by the area code 671. This geographic allocation covers the entire island, including the capital city of Hagåtña (formerly Agana), the major commercial hub of Dededo, and other populated villages such as Tamuning, Mangilao, and Tumon, the island's primary tourist district.

Dialing Formats and Procedures

For local calls within Guam, callers must dial the 10-digit number consisting of the area code and the 7-digit local number (e.g., 671-XXX-XXXX). This applies even for calls between adjacent villages, as there are no local exchange prefixes that allow abbreviated dialing. For international callers, the standard international dialing format is +1 671 XXX XXXX. From the United States mainland, callers can dial 1 671 XXX XXXX, as Guam is part of the NANP. However, it is crucial to note that calls from the U.S. mainland to Guam are typically billed as international calls, despite using the domestic country code 1. This is due to the distance and the involvement of international carriers. Conversely, calls from Guam to the U.S. mainland require dialing 1 followed by the area code and number, and are also billed as international calls.

Numbering and Regulatory Context

Guam's numbering plan is administered by the Guam Public Utilities Commission (PUC) under the oversight of the Federal Communications Commission (FCC). The area code 671 was introduced in 1997, replacing the previous international prefix 671 that was used for calls from other countries. As of now, there are no overlay codes or plans for an additional area code, as the current numbering resources are sufficient for the island's population of approximately 170,000. The 7-digit local numbers are allocated to various service providers, including the incumbent local exchange carrier (GTA TeleGuam) and other competitive carriers offering fixed-line, mobile, and VoIP services. Mobile numbers in Guam also use the 671 area code and are non-geographic within the island, meaning they are not tied to a specific physical location. When calling a Guam mobile number from abroad, the same international format +1 671 XXX XXXX applies. Number portability is available, allowing customers to retain their numbers when switching providers.

Practical Guidance for Callers

For businesses and individuals contacting Guam, it is essential to verify the correct dialing sequence with your carrier, as some international gateways may require a different access code. Always confirm the time zone difference (Guam is UTC+10, ahead of U.S. mainland time zones) to avoid calling at inconvenient hours. When storing Guam numbers in your contacts, use the international format +1 671 XXX XXXX to ensure proper dialing from any location. For travelers within Guam, local calls are typically included in hotel packages, but check with your service provider for roaming charges if using a foreign SIM card.