Ideal
Early Window
local
Guam numbers follow the same 10-digit NANP format as the US mainland, using the territory's dedicated 671 area code.
EST (UTC−5)
PST (UTC−8)
+1-671 · UTC+10
Best Time to Call
Guam
from the United States
Guam shares the +1 code with the US mainland, using its own dedicated 671 area code. From the US East Coast, business hours in Guam fall between 6:00 PM and 2:00 AM EST.
Best EST: 6:00 PM – 2:00 AM (+1 day)
Mon–Fri
United States
09:28 AM
Business hours
14h
difference
Guam
11:28 PM
Sleeping
// Best Time to Call
When to Call Guam
The overlap between US business hours and Guam business hours is during 6:00 PM–2:00 AM EST — a workable window for most teams.
Ideal
Prime Window
local
Answers about Guam's NANP numbering, business culture, and getting a local virtual number.
EST (UTC−5)
PST (UTC−8)
Avoid
Avoid
local
Outside business hours in Guam. Calls will likely go to voicemail or be unwelcome.
EST (UTC−5)
PST (UTC−8)
| Local Time | UTC | EST / New York | CST / Chicago | PST / LA |
|---|---|---|---|---|
| Open | ||||
| Noon | ||||
| PM | ||||
| Close |
// Calling Guide
How to call Guam — the short version.
Dial the right code, pick the right window, and your call to Guam goes through first time.
Dialing steps
- 1Dial your exit code — 011 from the US, 00 from most of Europe.
- 2Add the Guam country code: +1-671.
- 3Enter the local number, including any area code.
- 4Press call and confirm the time zone first.
Best time to call
- 9:00 AM – 5:00 PM local time in Hagåtña — most people are at their desk.
- That's 6:00 PM – 2:00 AM EST if you're calling from the US.
- The overlap between US business hours and Guam business hours is during 6:00 PM–2:00 AM EST — a workable window for most teams.
- Avoid calling outside local business hours — calls are less likely to be answered.
Quick tips
- Save the +1-671 code in your contacts so every call dials correctly.
- Guam business hours run Mon–Fri.
- Use a Rozper local virtual number to call as if you're already there — no per-minute international rates.
// Calling Etiquette
Guam Business Calling Etiquette
Cultural context for calling contacts in Guam — know what to expect before you dial.
Network & carriers
Guam's telecom market is served by GTA, IT&E, and DOCOMO Pacific as the major carriers.
Numbering format
Guam numbers follow the NANP 10-digit format using the dedicated 671 area code.
Calling culture
Business culture in Guam blends US and Pacific Islander traditions — a warm, relationship-oriented approach is typical.
Good to know
Guam shares its +1 country code with the US mainland, but its 671 area code is exclusive to the territory.
// Why Rozper
Built for Calling Guam at Scale
From crystal-clear audio to automatic CRM logging, here's what powers every call your team makes to Guam.
Guam Coverage, Included
Get a virtual number for Guam (+1-671) alongside 150+ other countries — no office required in Hagåtña.
HD Calls Across Oceania
Crystal-clear audio to Guam over our optimised carrier network — no degraded quality on the UTC+10 route.
Every Guam Call, Transcribed
Calls are recorded and transcribed automatically — handy when your Guam contacts speak English/Chamorro.
Never Miss a Call from Guam
Voicemails picked up outside the Mon–Fri work week are transcribed and delivered by email or SMS.
Guam Calls, Logged Automatically
Every call to or from your Guam number logs straight into Salesforce, HubSpot, or Zoho CRM — deal values in US Dollar.
Analytics for Your Guam Line
See call volume and answer rates for Guam, broken down by hour against UTC+10.
A Local Hagåtña Caller ID
Show a recognisable Hagåtña number when calling Guam — dramatically improves pickup rates.
Go Live in Guam in 60 Seconds
Activate your Guam virtual number instantly — no contracts, no hardware, no delays.
99.99% Uptime, Even to Guam
Enterprise-grade reliability for calls to Guam and 150+ other countries, with 24/7 expert support.
// Get Started
Start Calling Guam Today
Active in under ten minutes. No contracts or hardware needed.
- 01
Sign up for Rozper
Create your account in under 2 minutes. No credit card required to start your free trial.
- 02
Get a Guam virtual number
Browse available numbers in your target country. Pick a local or toll-free number that fits your needs.
- 03
Configure call routing
Route incoming calls to any device — mobile, desk phone, or browser. Set business hours and voicemail greetings.
- 04
Start calling internationally
Make and receive calls from your new international number. Active and ready in under 10 minutes.
// Complete List
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Every country and territory, every international dial code. Click a country to browse it.
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Frequently Asked
Calling Guam — Common Questions
Everything you need to know about reaching contacts in Guam.
The international dialing code for Guam is +1-671. To call Guam from the US, dial 011 + 1-671 + the local phone number (omitting the leading 0 if present).
Ready to call Guam?
Get a local Guam number or make international calls to +1-671 numbers — active in under ten minutes.
99.99% Uptime
150+ Countries
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