Area code 671: Guam
Area code 671 is a US territory area code for Guam, on Chamorro Standard Time. All 95 of its prefixes in service are in the Agana rate center. NANPA lists no overlay code for it. Local calls there take 10 digits.
Local time in area code 671
Pacific/Guam
Prefixes in service
95 of 792 possible
1 rate center
Area code 671 facts
| Location | Guam, United States |
|---|---|
| Time zone | Chamorro Standard Time |
| Overlays | None |
| In service since | July 1, 1997 |
| Local calls | 10 digits; toll calls 1 + 10 digits |
| Carrier | Not shown. An area code is where a number was issued; numbers port between carriers. Check line type |
Which cities and towns use area code 671?
NANPA records each prefix against a rate center, the local billing area a number belongs to, usually named after its main town. These are the 671 rate centers with the most prefixes in service.
| Rate center | Prefixes |
|---|---|
| Agana | 95 |
Source: NANPA central office code assignments, file dated 10/17/2026. Each prefix holds up to 10,000 numbers.
How do I dial a 671 number?
NANPA's dialling plan for 671: local calls inside the code take 10 digits, toll calls 1 + 10 digits. From another area code, dial 1 first. From abroad, use +1. The examples use 555-0147, from a range reserved for fictional numbers.
| Local call inside 671 | 671-555-0147 |
|---|---|
| From another US or Canadian area code | 1-671-555-0147 |
| From outside North America | +1 671 555 0147 |
| E.164, for CRMs and SMS tools | +16715550147 |
When did area code 671 start?
Area code 671 went into service on July 1, 1997. It has no overlay, so every number in its area still starts with it.
Tools for 671 numbers
- Area code lookup
Look up any code or a whole list of numbers, or find the codes for a state or city.
- Area code time zone
Local time for a list of numbers, with a callable-now flag.
- NPA-NXX lookup
Rate center and state for one prefix, a level below the area code.
- TCPA calling hours checker
Whether it's inside the federal 8 a.m. to 9 p.m. calling window there now.
Next step
A 671 number tells you where it was issued, not what it is now.
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Area code 671 questions
- What state or territory is area code 671?
- Area code 671 is in Guam, United States. Its largest rate centers by number of prefixes are Agana.
- What time zone is area code 671 in?
- Chamorro Standard Time.
- Does area code 671 have an overlay?
- Not as of NANPA's file dated 10/16/2026. Every number in its area uses 671.
- When did area code 671 start?
- Area code 671 went into service on July 1, 1997.
- Is a 671 number a cell phone or a landline?
- The area code can't tell you. In the US and Canada mobiles, landlines and VoIP lines share area codes and prefixes, and numbers move between carriers and line types. Only a live line-type lookup answers it for one number.
- How many phone numbers does area code 671 have?
- 95 of its 792 possible prefixes are in service, and each prefix holds up to 10,000 numbers. That counts prefixes assigned to carriers, not numbers in use.
Sources
Location, overlays, in-service date and dialling plan: NANPA NPA database, file dated 10/16/2026. Prefixes and rate centers: NANPA central office code assignments, 10/17/2026. Time zones mapped to the IANA time zone database. By the SimpleVerifier Team; how we build these pages.