How do I register Viettel's IFT international pack from my phone?

Send the SMS "IFT" to 133 from your Viettel number. You'll receive a confirmation and the pack activates immediately. The pack drops your rate to the US to around 500 VND/min and runs 30 days from activation. Other Viettel options include QT and TQ packs in different price tiers. Check your remaining balance with the SMS "KT IFT" to 133. The pack auto-renews unless you cancel by sending "HUY IFT" to 133 before the 30-day window closes.

Can I call the US for free from Vietnam over WiFi?

Yes, but only for app-to-app calls. WhatsApp, Zalo, Viber, FaceTime, Signal, and Telegram voice calls work over Vietnamese WiFi or mobile data and cost nothing extra. The person you're calling needs the same app installed and signed in. None of these reach US landlines, US business lines, or government agencies (IRS, USCIS, Chase, Bank of America). For those, you need a paid service — Viettel direct at 3,600 VND/min, a registered international pack at 500 VND/min, or a browser-based service at $0.04/min in USD.

Does *67 work from a Vietnamese phone to hide my caller ID?

No. *67 is a North American carrier code that only works on calls placed inside the United States and Canada. From a Vietnamese phone (Viettel, Vinaphone, Mobifone), there's no universal equivalent dialing code, and caller ID blocking depends on your carrier. Viettel and Vinaphone both offer a caller ID restriction service you can enable through their app or customer service line (198 for Viettel, 9191 for Vinaphone). On browser-based services like World Dialer, you can set or hide the outbound caller ID in your account settings without a per-call code.

Will Zalo connect to a US business line in 2026?

No. Zalo is Vietnam's dominant messaging app and supports voice calls between two Zalo users, but it doesn't include outbound calling to regular phone numbers — no Zalo Out, no PSTN bridge. Zalo works for calling family in California or Texas if both sides have the app. To reach a US bank, a US government office, or any number that doesn't have Zalo installed, you need a carrier call, a VoIP service, or a browser-based pay-as-you-go option.

Why does the first minute of a Vinaphone call to the US cost so much?

Vinaphone bills the first minute of an international call at the "rack rate" — roughly 36,500 to 45,500 VND — and subsequent minutes at the standard per-minute rate. The pricing model exists to push you toward registering a pack. If you call the US without the QT199 pack active (199,000 VND for 199 minutes over 30 days), expect the first 60 seconds of any call to cost more than the next ten minutes combined. To register QT199, send "DK QT199" via SMS to 900 from your Vinaphone number. Pack minutes drop the rate to around 1,000 VND/min.

How to Call US from Vietnam (Cheapest Way 2026)

To call the US from Vietnam, dial 00 + 1 + the US area code + the 7-digit number. On a mobile phone, you can use + instead of 00, so the IRS becomes +1 267 941 1000 and Chase Bank's international line becomes +1 713 262 3300. Vietnam's exit code is 00, not 011 — 011 is the US exit code, and confusing them is the most common mistake.

What you'll pay to call the US from Vietnam depends on whether you dial direct or buy a pack first. Viettel's standard rate is 3,600 VND/min. Mobifone is 4,114 VND/min via 00. Vinaphone's rack rate runs over 36,000 VND for the first minute. Here's how to pay $0.04 a minute instead, plus the US numbers that actually work from a Vietnamese network.

How to Dial the US from Vietnam

Vietnam's international exit code is 00. Dial it, then 1, then the US area code and 7-digit number.

Dial 00 (Vietnam's exit code) — or + on a mobile phone
Dial 1 (US country code)
Dial the 3-digit area code
Dial the 7-digit phone number
Example: 00 1 267 941 1000 reaches the IRS international line

That's the whole formula. If you've seen guides telling you to dial 011, that's the US exit code — used when calling FROM the US, not from Vietnam. From a phone in Hanoi or Ho Chi Minh City or Da Nang, you dial 00.

Calling from a Vietnamese landline? Same format. Calling from a hotel phone in Hoi An? Same format, plus whatever outside-line digit the hotel uses (usually 0 or 9). Vietnam's country code is +84 — you only need that to call INTO Vietnam, not out.

How to Call the US from a Vietnamese Cell Phone

From a Vietnamese cell phone, replace 00 with + and dial straight through. The dialing is the easy part. The harder part is what your carrier charges, and whether you're locked into a pack you won't use up.

Here's the rate reality:

Carrier / Plan | Rate to US | At 25,300 VND/USD

Viettel — direct (postpaid/prepaid via 00) | 3,600 VND/min | ~$0.14/min

Viettel — international pack (IFT/QT/TQ, register via SMS to 133) | 500 VND/min | ~$0.04/min

Vinaphone — standard IDD (rack) | ~36,500-45,500 VND first min | ~$1.40-$1.80 first min

Vinaphone — QT199 pack (199,000 VND/30 days, 199 min) | ~1,000 VND/min | ~$0.04/min

Mobifone — direct via 00 | 4,114 VND/min | ~$0.16/min

Mobifone — VoIP via 131 (cheaper rack) | 3,960 VND/min | ~$0.156/min

Notice the spread? Vinaphone bills the first minute at around 36,500 VND on the rack rate, then drops to roughly 1,000 VND on the QT199 pack. That's a 36x difference for the same call. The gap is not an accident. The rack rate exists so the pack looks like a deal. Viettel wants you on a pack. Vinaphone wants you on a pack. Mobifone wants you on a pack. And if you don't burn through the minutes inside the 30-day validity window, the balance expires.

If you call the US from Vietnam four or five times a year for family, visa, or banking work, a 299,000 VND pack is a poor fit. You use 40 minutes, the rest evaporates, and you do it again next month.

Do US Toll-Free Numbers Work from Vietnam?

US 1-800 numbers will ring through from Vietnam, but they aren't toll-free. Your Vietnamese carrier bills the call at full international rates.

This applies to every US toll-free prefix: 1-800, 1-888, 1-877, 1-866, 1-855, 1-844, 1-833. You dial 00 1 800 xxx xxxx (or +1 800 xxx xxxx on mobile), the call connects, and Viettel charges you 3,600 VND a minute for the privilege. Mobifone charges 4,114. Vinaphone charges its rack rate.

The fix: find the company's direct +1 (NXX) number. Banks, the IRS, USCIS, and the SSA all publish a non-toll-free line for international callers. Those route from any Vietnamese network and cost less than the 1-800 versions, regardless of carrier — and far less through a browser service.

Your Options for Calling the US from Vietnam

You have four ways to call the US from Vietnam. Most of them are designed to be paid for whether you use them or not.

Method | Cost | Setup | Best For

Vietnamese carrier — direct ISD | 3,600-4,114 VND/min | None | Single emergency call

Vietnamese carrier — international pack | 500-1,000 VND/min | Register pack 39K-299K VND/30 days | Daily callers who'll burn the minutes

VoIP subscription (Skype, Vonage) | ~$10-$30/mo + per-min | App, account, credit card | Frequent international callers

WorldDialer (browser) | $0.04/min | None | Occasional callers

VoIP subscriptions assume you'll call internationally every week. Most family-in-Vietnam callers won't. You're in Saigon, you need to sort out a Chase fraud alert, then you don't dial a US number for three months. Paying $15 a month for that is paying for the months you don't call.

Carrier packs have the same problem in dong. The 199,000 VND QT199 pack buys 199 minutes. Use 30 of them and 169 minutes expire. Pay again next month.

WorldDialer runs in a browser. No app. No pack. No monthly subscription required. Open the tab, add credits, make the call. $0.04 a minute to US landlines, the same rate whether you're in Hanoi or Ho Chi Minh City.

US Phone Numbers You'll Need from Vietnam

These are the non-toll-free US numbers that work from any Vietnamese network. Bookmark them. The 1-800 versions will charge you international rates.

Institution | Number | Hours (US Eastern)

Chase Bank | +1 (713) 262-3300 | 24/7

Bank of America | +1 (315) 724-4022 | Mon-Fri 7 AM-10 PM, weekends 8 AM-5 PM

IRS International | +1 (267) 941-1000 | Mon-Fri 6 AM-11 PM

USCIS International | +1 (212) 620-3418 | Mon-Fri 8 AM-8 PM

For Social Security, the Office of Earnings and International Operations answers at +1 (410) 965-0160, Mon-Fri 9 AM-4 PM ET. The IRS, SSA, and USCIS all publish these numbers on .gov sites — they're set up for calls from overseas. Calling US banks from abroad covers the wider bank list.

A 15-minute call to Chase:

On Viettel direct (3,600 VND/min): 54,000 VND (~$2.13)
On Viettel pack (500 VND/min): 7,500 VND (~$0.30) — plus the cost of the pack
On WorldDialer: $0.60

Same Chase. Different bill.

When to Call the US from Vietnam

Vietnam is on Indochina Time, 12 hours ahead of US Eastern in winter and 11 hours ahead in summer (subtract one hour during US daylight saving). ICT doesn't shift; the US side moves twice a year.

US East Coast 9 AM-5 PM = 9 PM-5 AM ICT (winter)
IRS opens at 6 AM ET = 6 PM ICT — early evening, post-work
USCIS opens at 8 AM ET = 8 PM ICT — after dinner
West Coast 9 AM-5 PM = midnight-8 AM ICT (winter) — overnight

The 6 PM ICT IRS-opens window is a genuine geographic advantage. Most countries get an awkward pre-dawn hour to reach US institutions. Vietnam gets a workable early-evening slot — call the IRS the moment they open and skip the queue. For Vietnamese-American families coordinating between Orange County and Da Nang, the same window works for Chase or Bank of America. Dinner in California is mid-morning in Vietnam. Late afternoon in Vietnam is the start of the US workday.

Call US Numbers from Vietnam

You have the format, the numbers, and the rates. Time to dial.

WorldDialer works from Vietnam. $0.04/minute to US landlines. Browser-based, no app to install, no pack to expire, no monthly subscription required.

Next time you need to call US, we'll be here.

→ Try WorldDialer

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