Ideal
Early Window
local
Vietnamese mobile numbers drop their leading 0 internationally, and most now follow a 10-digit format after the country's 2018 renumbering.
EST (UTC−5)
PST (UTC−8)
+84 · UTC+7
Best Time to Call
Vietnam
from the United States
Vietnam's +84 code covers one of Southeast Asia's fastest-growing mobile markets, led by state-linked carrier Viettel. From the US East Coast, business hours in Vietnam fall between 9:00 PM and 5:00 AM EST.
Best EST: 9:00 PM – 5:00 AM (+1 day)
Mon–Fri
United States
09:29 AM
Business hours
11h
difference
Vietnam
08:29 PM
Outside office
// Best Time to Call
When to Call Vietnam
Vietnam business hours overlap with US afternoon/evening. Plan calls for after 3 PM EST to reach their morning.
Ideal
Prime Window
local
Answers about Vietnam's carrier landscape, hierarchy-aware calling etiquette, and getting a local +84 virtual number.
EST (UTC−5)
PST (UTC−8)
Avoid
Avoid
local
Outside business hours in Vietnam. 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 Vietnam — the short version.
Dial the right code, pick the right window, and your call to Vietnam goes through first time.
Dialing steps
- 1Dial your exit code — 011 from the US, 00 from most of Europe.
- 2Add the Vietnam country code: +84.
- 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 Hanoi — most people are at their desk.
- That's 9:00 PM – 5:00 AM EST if you're calling from the US.
- Vietnam business hours overlap with US afternoon/evening. Plan calls for after 3 PM EST to reach their morning.
- Avoid calling outside local business hours — calls are less likely to be answered.
Quick tips
- Save the +84 code in your contacts so every call dials correctly.
- Vietnam 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
Vietnam Business Calling Etiquette
Cultural context for calling contacts in Vietnam — know what to expect before you dial.
Network & carriers
Vietnam's telecom market is regulated by the MIC, with Viettel, VinaPhone, and MobiFone as the three major carriers.
Numbering format
Vietnamese mobile numbers are 9 or 10 digits depending on carrier, with the leading 0 dropped internationally.
Calling culture
Vietnamese business culture places importance on respect and hierarchy — addressing contacts formally and building trust over time is standard practice.
Good to know
Vietnam renumbered its entire mobile numbering system in 2018, shifting millions of subscribers to new 10-digit numbers to accommodate growth.
// Why Rozper
Built for Calling Vietnam at Scale
From crystal-clear audio to automatic CRM logging, here's what powers every call your team makes to Vietnam.
Vietnam Coverage, Included
Get a virtual number for Vietnam (+84) alongside 150+ other countries — no office required in Hanoi.
HD Calls Across Asia
Crystal-clear audio to Vietnam over our optimised carrier network — no degraded quality on the UTC+7 route.
Every Vietnam Call, Transcribed
Calls are recorded and transcribed automatically — handy when your Vietnam contacts speak Vietnamese.
Never Miss a Call from Vietnam
Voicemails picked up outside the Mon–Fri work week are transcribed and delivered by email or SMS.
Vietnam Calls, Logged Automatically
Every call to or from your Vietnam number logs straight into Salesforce, HubSpot, or Zoho CRM — deal values in Vietnamese Đồng.
Analytics for Your Vietnam Line
See call volume and answer rates for Vietnam, broken down by hour against UTC+7.
A Local Hanoi Caller ID
Show a recognisable Hanoi number when calling Vietnam — dramatically improves pickup rates.
Go Live in Vietnam in 60 Seconds
Activate your Vietnam virtual number instantly — no contracts, no hardware, no delays.
99.99% Uptime, Even to Vietnam
Enterprise-grade reliability for calls to Vietnam and 150+ other countries, with 24/7 expert support.
// Get Started
Start Calling Vietnam 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 Vietnam 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
All world dial codes by country.
Every country and territory, every international dial code. Click a country to browse it.
List of World Countries and Their Dial Codes
CountryDial CodeRegionLocal Time
Showing all 237 countries & territories* Local time updates every minute
Frequently Asked
Calling Vietnam — Common Questions
Everything you need to know about reaching contacts in Vietnam.
The international dialing code for Vietnam is +84. To call Vietnam from the US, dial 011 + 84 + the local phone number (omitting the leading 0 if present).
Ready to call Vietnam?
Get a local Vietnam number or make international calls to +84 numbers — active in under ten minutes.
99.99% Uptime
150+ Countries
24/7 Expert Support
No contracts