A tourism information kiosk offering free maps and hotel booking services at Noi Bai International Airport in Hanoi.

Travel guide

Staying online from Saigon to the far north

Mobile data in Vietnam is fast, cheap and nearly everywhere. A local SIM or an eSIM, registered to your passport, is the easy answer. The exceptions are a few deep valleys, caves and the open sea.

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Overview

The simple answer

Last checked 22 September 2026

We check this page every three months, and after any change to the rules for registering SIM cards, which the government has tightened more than once in recent years. We name the mobile networks because they are the country’s own; we do not recommend a particular eSIM seller.

For most travellers, the best set-up is a local data SIM or an eSIM with a few weeks of data. It costs little, it gives you maps, ride-hailing and messaging everywhere, and it means our guides and the 24/7 line can always reach you. Roaming on your home plan works too, and is simplest if your provider has a reasonable daily rate for Vietnam; check before you land.

Networks: Viettel, Vinaphone, Mobifone
Local SIM: Airport, phone shops
eSIM: Works on compatible phones
Registration: Passport required
Coverage: Good almost everywhere
Wi-Fi: In nearly every hotel and café

SIM and eSIM

Buying a SIM or eSIM

Vietnam has three main mobile networks, Viettel, Vinaphone and Mobifone, and several smaller ones that use their infrastructure. Viettel generally has the widest coverage in the mountains and rural areas. You can buy a tourist SIM at the arrivals halls in Saigon, Hanoi and Da Nang, or at the networks’ own shops in any town.

01
Bring your passport
Every SIM in Vietnam must be registered to the user’s identity, and for visitors that means the passport. The seller takes the details and often a photo of you.
02
Choose a data package
Tourist packages are sold by days and gigabytes. A month of generous data is inexpensive by international standards.
03
Check it before you leave the counter
Make sure data works and note the number. Keep your home SIM somewhere safe if you swap.
04
For eSIM
Buy from a network or a reputable seller before you fly, install it at home, and switch it on when you land. The same identity rules can apply.

An unlocked phone is needed for a local SIM. Most phones bought outright are; phones on a contract may not be. An eSIM needs a phone that supports it, which most recent models do.

Ho Chi Minh City Hall glows at night with its French colonial facade and flag-topped clock tower.

A bamboo beach deck with red flowering trees and string lights overlooks turquoise sea along the Hue to Hoi An coast.

Arrivals-hall counters are the easiest place to buy. · Café Wi-Fi is usual, and usually good.

Coverage

Where coverage stops

Mobile coverage across Vietnam is good: 4G is available in nearly every town, along the main roads and on most of the coast, and 5G is spreading in the big cities. You will be online on the delta boats, on Phu Quoc and in most of the mountains. The gaps are where you would expect them.

Where	What to expect
Deep valleys in Ha Giang and Cao Bang	Signal drops between villages for stretches of the loop
Inside the caves at Phong Nha	Nothing underground; signal at the entrances
Ha Long and Lan Ha cruises	Patchy away from the islands; boat Wi-Fi is often slow
Trekking routes above Sapa and in Pu Luong	Intermittent
Con Dao and remote islands	Good in the main town, weaker elsewhere

Download offline maps for the regions you are visiting before you go, and tell someone your plans if you are trekking. On our tours in these areas the guide carries a phone on the strongest local network and knows where the signal comes back.

A turquoise river winds through deep misty canyons near the Ma Pi Leng Pass in Ha Giang. — Stretches of the Ha Giang loop have no signal at all.

Apps

Apps that help here

A ride-hailing app: Grab, and the local alternatives Be and Xanh SM, for cars and motorbike taxis in the cities.
Maps with offline areas downloaded, for the mountains and the delta.
A translation app with the camera function, for menus and signs.
WhatsApp, which we use with travellers. Zalo is the messaging app most Vietnamese use, and some hotels and drivers prefer it.
Your bank’s app, with notifications on, so you see every card payment.

Power

Power and charging

Vietnam uses 220 volts, and sockets usually take two-pin plugs, both round and flat pins. Most phone and laptop chargers work on any voltage; check the small print. A universal adapter and a power bank for long road days are the two things we suggest carrying. Hotels usually have sockets by the bed; sleeper trains and boats have fewer.

Common questions

Questions travellers ask most

Do I really need a local number?

Not strictly, but it makes life easier: ride-hailing apps work better with one, and Vietnamese hotels and drivers can call you. Data alone, on an eSIM, covers most needs.

Can I use my home phone number and a local data eSIM together?

Yes, on phones with dual SIM support. Keep your home line on for calls and messages from your bank, and use the eSIM for data.

Is public Wi-Fi safe to use?

For browsing and maps, yes. For banking, use mobile data or a VPN, as you would anywhere.