How to install a Vietnam eSIM (and what to do when it goes wrong)
The install itself takes four minutes. What catches travellers out is everything around it — a locked phone, a QR that only scans once, and the apps in Vietnam that still want a local number.
· 9 min read
Installing an eSIM is genuinely easy — four taps on an iPhone, five on Android. Almost nobody gets stuck on the installation.
What does catch people out is everything around it: discovering at the gate that their phone is carrier-locked, scanning the QR twice and burning it, landing with data but no Vietnamese number for the Grab driver, or turning the eSIM on a week early and watching the validity tick away while they're still at home.
This guide covers the install, then the parts that actually cause problems.
First: check your phone can actually use an eSIM
Two things have to be true. Your phone must have eSIM hardware, and it must not be carrier-locked. People check the first and forget the second, which is the single most common reason a traveller ends up with an eSIM they can't install.
To check the hardware, look for an EID number:
- iPhone: Settings › General › About, scroll to EID. Or dial *#06# and look for an EID line.
- Android: Settings › About phone › Status, or dial *#06#.
No EID means no eSIM support, and there is no software fix. Broadly, iPhone XS and newer, Google Pixel 3 and newer, and recent Samsung Galaxy S, Note and Z models all qualify.
Carrier locking is the other half. If you bought the phone on a contract or instalment plan and haven't finished paying, it may only accept SIMs from that carrier. Ask your carrier to unlock it before you travel — it is usually free once the contract is settled, but it can take a few business days, so it is not a same-day fix at the airport.
Installing on iPhone
Do this at home, on Wi-Fi, before you fly. You need an internet connection to download the profile, and doing it early means you land already set up.
- 1Connect to Wi-Fi.
- 2Open Settings › Cellular (called Mobile Service on some iOS versions).
- 3Tap Add eSIM, then Use QR Code.
- 4Scan the QR code from your confirmation email. If the code is on the same phone, tap Enter Details Manually and paste the activation code instead.
- 5When asked to label the line, name it something obvious like "Vietnam".
- 6Keep your home line as the default for calls and iMessage.
- 7Turn the Vietnam line OFF for now — Settings › Cellular › Vietnam › toggle off.
That last step matters more than it looks. Leaving the line off means the profile is installed and waiting, but hasn't connected to a Vietnamese network yet — so your validity period hasn't started.
Installing on Android
Menu names vary a little between manufacturers, but the flow is the same.
- 1Connect to Wi-Fi.
- 2Open Settings › Network & internet › SIMs.
- 3Tap Add eSIM, or the + next to SIMs.
- 4Choose "Download a SIM instead?" and scan the QR code.
- 5Confirm the download and name the profile "Vietnam".
- 6Leave the profile disabled until you arrive.
On Samsung devices the path is Settings › Connections › SIM manager › Add eSIM. On Pixel it is exactly as listed above.
When you land in Vietnam
- 1Turn on the Vietnam eSIM line in your settings.
- 2Enable Data Roaming for that line. This is required and does not cost extra — the eSIM is technically roaming onto Viettel.
- 3Set the Vietnam line as your Mobile Data line.
- 4Make sure your home line's data roaming stays OFF, or your own carrier will happily bill you alongside the eSIM.
- 5Wait up to two minutes for the network to register. If it stalls, toggle airplane mode on and off.
When does the validity actually start?
Validity starts when the eSIM first connects to a Vietnamese mobile network — not when you buy it, and not when you install it.
This is why installing early is safe. You can buy a 15-day plan three weeks before your trip, install it the same evening, and still get the full 15 days from the moment you land.
The trap is turning the line on while you are still at home and within range of a network that the profile will attach to. Leave it off until the plane doors open.
The part most guides skip: you may still need a Vietnamese number
Most travel eSIMs, including the cheaper plans here, are data-only. That covers maps, browsing, and calls over WhatsApp, Zalo, Messenger and FaceTime — which is 90% of what travellers need.
But some things in Vietnam genuinely want a local phone number:
- Grab drivers often call rather than message, especially outside the big cities. With a data-only eSIM they cannot reach you by phone.
- Some restaurant and hotel bookings ask for a local number for confirmation.
- Vietnamese banking apps and e-wallets (Momo, ZaloPay) require a Vietnamese number to register — relevant if you are staying long enough to want one.
- A few delivery services will not accept an international number at checkout.
Two practical fixes. Either choose a plan that includes a local number — our unlimited plans do — or keep in-app chat turned on in Grab and message the driver rather than relying on a call. For a short holiday, data-only plus in-app chat is usually fine. For a longer stay, or if you're travelling outside Hanoi, Ho Chi Minh City and Da Nang, a local number is worth the extra few dollars.
Coverage, speed and where it actually gets thin
Our plans run on Viettel, which has the widest coverage in Vietnam — it is the network Vietnamese people use in the places tourists don't reach.
| Where | What to expect |
|---|---|
| Hanoi, Ho Chi Minh City, Da Nang | Strong 5G in central districts, 4G everywhere else |
| Hoi An, Nha Trang, Hue, Phu Quoc | Reliable 4G, 5G in tourist centres |
| Ha Giang loop, Sapa, Cat Ba | Good 4G on main roads, patchy in valleys and on passes |
| Long-distance buses and trains | Usable but intermittent — download offline maps first |
| Halong Bay overnight cruises | Signal near shore, little to none further out |
Every plan carries 5GB per day at full 5G speed. Worth checking against whatever else you are comparing: most travel eSIMs sold for Vietnam are roaming products on 4G, and they cap lower — Airalo drops to 1Mbps after 3GB a day, Nomad to 512Kbps after 2GB, both too slow for Grab or Maps to stay usable.
eSIM or a physical SIM at the airport?
An honest comparison, because the eSIM is not automatically the right answer.
| Travel eSIM | Physical SIM at the airport | |
|---|---|---|
| Setup | Before you fly, at home | Queue on arrival, passport required |
| Your home number | Stays active alongside | Removed while the local SIM is in |
| Local number included | Only on some plans | Always |
| Price | Fixed and visible before you buy | Varies; arrivals-hall pricing is often higher |
| If it fails | Support by email; needs data or Wi-Fi | Walk back to the counter |
| Phone must be unlocked | Yes | Yes |
Choose the eSIM if you want your home number to keep working, you'd rather not queue after a long flight, and you want the price settled in advance. Choose a physical SIM if your phone has no eSIM support, you need a local number cheaply, or you'd rather have a human at a counter to complain to.
The five failures that actually happen
In rough order of frequency.
- 1"No service" after landing. Nine times out of ten, Data Roaming is off for the eSIM line. Turn it on, then toggle airplane mode. If it still fails, go to Network Selection, turn off Automatic, and pick Viettel manually.
- 2"This code is no longer valid." A QR installs exactly once. If you scanned it twice, or installed then deleted the profile, it cannot be reused — the profile is gone. Contact us with your order reference rather than buying a replacement; if it genuinely failed on our side we will reissue.
- 3Installed but no data, and roaming is already on. Check the Vietnam line is selected as your Mobile Data line, not just enabled. Both settings exist and doing one without the other is a common miss.
- 4Data suddenly slow. Either you've passed the daily allowance on an unlimited plan, or you've drifted back onto your home line. Check which line is carrying data before assuming it's the network.
- 5Everything worked, then stopped after a few days. Usually the plan has expired — validity counts calendar days from first connection, not days of use.
A short pre-flight checklist
- EID confirmed, phone unlocked.
- eSIM profile installed and labelled, line switched off.
- Home line's data roaming off.
- Offline maps downloaded for your route.
- Order reference and support contact screenshotted.
- Grab installed and logged in while you still have reliable internet.
Frequently asked questions
- Can I install the eSIM after I land?
- Yes, but you need internet to do it — hotel or airport Wi-Fi. Installing before you fly is easier and means you're connected the moment you switch off airplane mode.
- Can I move the eSIM to another phone?
- No. An eSIM profile installs onto one device and cannot be transferred or re-scanned. If you change phones mid-trip you need a new eSIM.
- Will I lose my normal phone number?
- No. The eSIM is a second line. Your home SIM stays active for calls, SMS and banking codes while the eSIM carries data. Just keep your home line's data roaming switched off.
- What happens if I run out of data?
- Each plan gives 5GB per day, which is more than most travellers use — maps and messaging run at roughly 300-500MB a day, and even steady video calls rarely reach it. The allowance resets daily, so the usual constraint is days rather than gigabytes. If your trip is extended, buy another eSIM; installation takes a couple of minutes.
- Does the eSIM work in Cambodia or Laos?
- No. These plans are Vietnam-only. Crossing the border means no service until you return, so if you're doing a multi-country trip you need separate arrangements for each.
- Can I use the eSIM as a hotspot?
- Yes, on every plan, at no extra cost. Tethering a laptop counts against the same allowance, so budget for it — video calls and cloud backups eat data quickly.