Why a Local SIM Is the First Piece of Infrastructure You Need Here
There are plenty of things you can postpone when you arrive in Vietnam. Finding the perfect apartment. Working out which bánh mì place deserves your loyalty. Learning why Google Maps thinks your motorbike can drive through a wall.
Don’t wait too long to get a Vietnamese phone number.
Your foreign number will roam happily enough. WhatsApp works, messages arrive, and for the first few days you may wonder why anyone bothered telling you to buy a local SIM.
Then you try to open a bank account.
Vietnamese number, please.
And soon you discover the same requirement elsewhere. Grab wants your number. Delivery apps want it. E-wallets want it. Your electricity account may want it. And then there is Zalo, where your landlord, building management and approximately every plumber, electrician and air-conditioner repairman in Vietnam seem to conduct their affairs.
More importantly, your Vietnamese bank account will rely heavily on your phone. Authentication, account notifications and one-time passwords are tied to it.
So treat your phone number as infrastructure rather than a convenience. Ideally, get it before you go to the bank.
Buy the Number, Not Just the SIM
Getting one is easy. Getting one properly registered to you is the important part.
Bring your original passport and valid immigration documents to an official carrier shop. Your SIM should be registered in your own name and linked to your identity.
In Vietnamese, you’ll often hear the term chính chủ, meaning roughly that you are the legitimate registered owner of the number.
That distinction matters.
A cheap pre-activated SIM registered to somebody else may work perfectly well until, suddenly, it doesn’t. If the carrier requires verification, the registered owner is not you. More importantly, you do not want a number of uncertain ownership sitting at the centre of your banking and other important accounts.
My preference would be boring and official: go to a proper Viettel, VinaPhone or MobiFone outlet and register the number yourself.
This is one occasion when boring is excellent.
SIM Registration Got Stricter in 2026
Vietnam tightened its subscriber-verification rules considerably this year.
Circular 08/2026/TT-BKHCN took effect on 15 April 2026 and introduced stronger identity verification for mobile subscribers. Foreign nationals are covered too, with identity information checked against the relevant immigration records and biometric verification used as part of the process.
Then came another change on 15 June 2026.
Move your SIM to another phone and you may have to verify your face again. The carrier can suspend outgoing calls and SMS within two hours while waiting for that verification. If you still haven’t completed it after 30 days, two-way service can be suspended; after another five days, the number can ultimately be withdrawn.
That sounds rather dramatic for something as mundane as changing phones, but there is a reason for it. Vietnam has been trying to clean up the enormous ecosystem of anonymous, pre-activated and fraudulently registered SIM cards. The government said in July that more than 99 million subscriptions had successfully been verified, while roughly 12 million were already under one-way suspension for failing to complete the process.
For the average foreign resident, the lesson is much simpler:
When your carrier asks you to verify something, don’t put it in the “I’ll do that later” pile.
The phone number connected to your bank account is a particularly bad thing to discover has stopped working.
Prepaid Is Usually All You Need
For most newcomers, prepaid is the obvious starting point. There is no need to turn buying a phone number into a telecommunications thesis.
Vietnam has three major traditional mobile networks: Viettel, VinaPhone and MobiFone. All offer inexpensive prepaid data packages, and mobile data in Vietnam is cheap enough that newcomers from Europe or North America may briefly suspect somebody has forgotten a zero.
Pick a sensible monthly package, make sure the SIM is registered to you, and keep the number.
That last part is more important than chasing whichever carrier happens to offer another gigabyte or two this month. Once the number is attached to your bank, apps, landlord, delivery accounts and assorted Vietnamese bureaucracy, changing it becomes administrative whack-a-mole.
Be Careful With Travel eSIMs
Travel eSIMs are brilliant for getting online immediately after landing. They are not necessarily a replacement for a Vietnamese SIM.
Many are data-only. You get internet access but no Vietnamese mobile number.
That’s perfectly fine for Google Maps and messaging apps. It doesn’t solve the problem this article is about.
If you buy an eSIM before travelling, check whether it includes an actual Vietnamese number and whether that number is registered to you. Otherwise, think of it as temporary internet access rather than your Vietnamese phone line.
The Short Version
Arrive in Vietnam. Find an official carrier shop. Bring your passport. Get a Vietnamese number registered in your own name.
Then go to the bank.
It is a small bit of bureaucracy that quickly becomes the anchor for everything else: banking, apps, deliveries, your apartment and the surprisingly large portion of Vietnamese life conducted through Zalo.
You will probably forget about the SIM within a week.
Which is exactly what you want from infrastructure.
