Asia
SIP Trunk Vietnam — +84 Termination & DID Numbers
Vietnam renumbered its mobile network in 2018, moving from 11 digits to 10. Some older customer databases still hold the retired 01xx prefixes and need converting before you dial. Ho Chi Minh City and Hanoi are both growing IT-outsourcing hubs.
Overview
Routing calls to Vietnam
Traffic to Vietnam leaves our SBCs on more than one upstream carrier per prefix. If a leg toward Hanoi or Ho Chi Minh City starts returning 503s or long post-dial delay, the next attempt goes to another carrier automatically. Calls to Da Nang, Hai Phong and Can Tho follow the same failover logic.
Inside the country, numbers are dialled with a 0 trunk prefix. Strip it before you send the call, and send 84 followed by the national number. On the rate sheet, Vietnam is split into geographic, mobile and toll-free prefixes, following the plan set by the national telecom regulator, so your LCR can tell a cheap fixed-line call from a pricier mobile one.
Outbound calls to Vietnam work on a standard account. Inbound DIDs are restricted, and options depend on licensing and current stock, so our team confirms availability before taking an order.
What you get
What you get in Vietnam
One account and one balance, with the same SBCs for termination and inbound numbers.
CLI route tier
Caller ID delivered end to end on +84 calls. Use it for sales, support and any traffic where answer rates matter.Non-CLI route tier
A lower-cost tier where caller ID delivery is not guaranteed. Suitable for internal or transactional traffic that does not depend on the CLI.Number types
Geographic, Mobile, Toll-free. DID availability varies by range and city.Codecs
G.711a/u and G.729 on every route, G.722 and Opus where the far end supports them. T.38 for fax.Channels on demand
Concurrent call limits are set per account and raised as your traffic grows. No fixed channel bundles.Multi-carrier failover
Every +84 prefix is mapped to more than one carrier. Failed attempts move to the next one automatically.
Number formats
How to dial Vietnam from your PBX
Send E.164 digits. The sample number below shows the format only.
| Format | Example | Notes |
|---|---|---|
| International (E.164) | +84 24 1234 5678 | How the number is written and stored. |
| Sent from your PBX | 842412345678 | E.164 digits with no plus, prefixed by your tech prefix if your account uses one. |
| With 00 exit code | 00 84 24 1234 5678 | Accepted on the trunk. We normalise it to E.164. |
| National format | 024 1234 5678 | Dialled inside Vietnam. Strip the trunk prefix before sending. |
Compliance
Vietnam rules to know
What applies before your first call or your first DID goes live.
Compliance box
- Regulator
- The national telecom regulator
- Caller ID
- A valid CLI that you are entitled to use is required on CLI routes. Spoofed or unallocated numbers are blocked.
- DID KYC
- Check with sales
Rules change — our team confirms current requirements before activation.
Use cases
Who uses Vietnam routes
- 01
Software outsourcing firms in Ho Chi Minh City and Da Nang calling clients abroad
- 02
Diaspora calling from the US and Australia into Vietnam
- 03
Manufacturing and export businesses calling factories in the north
Setup
Start calling Vietnam in 3 steps
- 01
Top up $200
Open a prepaid account and add balance by USDT (TRC20), BTC or card. - 02
Add your trunk
Whitelist your PBX IP or create digest credentials, then point your outbound route at our SBC. - 03
Dial +84
Send 84 + national number in E.164 and check the CDR for your first test call.
Further reading: SIP Error Codes 401, 403, 404, 408, 480, 486, 503: Causes and Fixes
FAQ
Vietnam SIP trunk questions
Why do some Vietnamese mobile numbers fail?
Old 11-digit 01xx mobile numbers were converted to 10 digits in 2018. Update stored numbers to the new 03/05/07/08 prefixes.
What are the main area codes?
Hanoi 024 and Ho Chi Minh City 028.
Who regulates Vietnamese telecoms?
The national telecom regulator. We confirm current requirements before activation.
Can I get Vietnamese DIDs?
Availability is limited. Ask sales.
