What "gói cước 4G Mobi" actually means
Break the phrase down and it stops being mysterious:
- Gói cước — package, tariff or plan.
- 4G — the data network generation the plan runs on.
- Mobi — MobiFone, one of Vietnam's three main mobile networks.
So a gói cước 4G Mobi is a MobiFone prepaid data bundle. Vietnamese subscribers buy these constantly: a short top-up package for a week, a monthly package, or a data-only bundle stacked on top of a voice plan. The codes are sold exactly as they appear in the carrier's catalogue — for example a plan sold under a code like V90B is bought by that code, not by a description.
Who actually buys one
There are two very different readers behind this search, and the right answer depends on which one you are.
| You are… | What fits |
|---|---|
| A Vietnamese subscriber with a MobiFone SIM | A gói cước 4G Mobi bought through MobiFone's own channels |
| A traveller arriving in Vietnam for days or weeks | A Vietnam eSIM bought before departure |
| A long-stay visitor with a local SIM already in hand | A carrier top-up package from the network that issued the SIM |
| Someone who wants one number for calls and one for data | A dual-SIM setup: physical local SIM plus travel eSIM |
The friction for the second and third rows is the same: buying a carrier package normally requires a Vietnamese SIM, a Vietnamese payment method in many cases, and enough Vietnamese to navigate a USSD menu. That is a lot of work for a two-week trip.
Why travellers usually want the eSIM instead
A travel eSIM skips the queue at the airport, the passport registration for a local SIM and the language barrier at the counter. You install it at home, it connects when you land, and the data allowance is fixed and visible before you pay.
If you are weighing the two, our comparison of Viettel, VinaPhone and MobiFone explains how Vietnam's three networks differ, and Pocket Wi-Fi or eSIM for your trip to Vietnam? covers the hardware alternative honestly.
What to buy, and where
The straightforward answer for a visitor is a Vietnam eSIM from VietSIM, bought before you fly:
- Short trip, light use — a small data bundle is enough for maps, messaging and Grab.
- One to two weeks, normal use — a mid-size plan covers navigation, translation, bookings and photos.
- Heavy use, hotspotting, remote work — go larger, and read Vietnam eSIM as a Hotspot first, because tethering eats data faster than phone-only use.
- "Unlimited" plans — read the fair-use terms before assuming. Vietnam eSIM Unlimited explains what the word really covers.
You can see current plans and buy in one step at the Vietnam eSIM store.
If you do want a local MobiFone SIM
It is a legitimate option, particularly for stays of a month or more. Expect to:
- Buy the SIM from a MobiFone shop or an authorised dealer — airport kiosks are convenient but priced for convenience.
- Register the SIM with your passport, as Vietnamese law requires.
- Ask the staff to activate the data package you want, or dial the carrier's own USSD code yourself.
- Keep the SIM topped up, because prepaid packages expire.
For a shorter trip, the time cost rarely pays off. Our Vietnam eSIM activation guide walks through the alternative: install before departure, activate on landing, and fix first-connection problems if they appear.
Check your phone before you choose
An eSIM only works on a compatible, carrier-unlocked handset. Two guides cover the common cases:
- Vietnam eSIM for iPhone — compatibility, dual-SIM behaviour and keeping WhatsApp on your usual number.
- Vietnam eSIM for Android — setup and the phones that work.
If your phone is not eSIM-capable, a physical local SIM is the fallback, and the airport guides are the place to start.
A note on plan codes
Carrier plan codes are quoted exactly as they are sold. If you see a code like V90B in a MobiFone catalogue, that is the string you enter or say — not a paraphrase. VietSIM's catalogue pages for Vietnamese readers list plans by their real codes so nothing gets lost in translation.