Why the Old Quarter changes the answer
Hanoi's Old Quarter is dense: narrow streets, tall tube houses, and a lot of concrete between you and the nearest mast. That matters less than you would think, because the three national networks — Viettel, VinaPhone and MobiFone — all run dense urban coverage here. The practical question is not "will it work?" but "how do I get it, and what does it cost?"
If you are arriving at Noi Bai and heading straight into the city, read Hanoi airport to the Old Quarter for the transport side, and Noi Bai Airport SIM Card for what is actually sold in the terminal.
eSIM or physical SIM in Hanoi?
| eSIM | Physical SIM | |
|---|---|---|
| When you can buy it | Before you fly | On arrival or in the city |
| Where it works | Any phone with eSIM support | Any unlocked phone |
| Airport queue | None | Depends on the counter |
| Keep your home number | Yes, as a second line | Only if you have a dual-SIM phone |
| Best for | Short trips, one phone, minimal admin | Longer stays, older phones, local calls |
An eSIM is a data plan delivered as a QR code or app profile. You install it before departure and it activates when it connects in Vietnam. A physical SIM is a plastic card you insert; it usually comes with a Vietnamese phone number, which matters if you need to make local calls or receive SMS.
For the detail on how each behaves, see Vietnam SIM card: what to know before you buy one and Does a Vietnam eSIM come with a phone number?.
What actually works in the Old Quarter
All three networks cover central Hanoi. In practice:
- Viettel has the largest national footprint, which matters if you are leaving Hanoi for Ha Giang, Sapa or Cat Ba.
- VinaPhone and MobiFone are strong in cities and along the main tourist routes.
- 5G is live in parts of Hanoi on some networks; check 5G in Vietnam for what that means for a traveller.
Inside the Old Quarter itself, expect usable data on any of the three. The places where coverage gets thinner are the ones outside the city: the far side of Hoan Kiem at night is fine; a homestay in the mountains is a different question.
Buying a SIM in Hanoi: the three routes
1. At Noi Bai Airport. Convenient, open around the clock, priced for arrivals. Counters sell tourist SIMs with a set data allowance and validity. See Noi Bai Airport SIM Card for what is on offer and the opening hours.
2. In the city. Carrier shops (Viettel, VinaPhone, MobiFone) in Hoan Kiem and around the Old Quarter sell official plans. You will need your passport. This is the cheapest route if you have time and want a local number.
3. Online, before you fly. An eSIM bought from a store like ours is installed at home and works on landing. No queue, no passport check at a counter, no risk of a vendor selling you a recycled tourist SIM.
What to check before you buy
- Phone compatibility. Your phone must be eSIM-capable and carrier-unlocked. Check the phone compatibility page before you pay.
- Data amount. A few days of maps, Grab and messaging is modest; streaming and hotspotting is not. See How much mobile data do you need in Vietnam?.
- Validity window. Plans run for a set number of days from activation, not from purchase.
- Hotspot. If you plan to share data with a laptop or a travel companion, confirm the plan allows it.
Installing and activating
If you buy an eSIM, install it before you leave home while you still have reliable Wi-Fi. Do not activate it until you are close to departure, because the validity clock starts on first connection in Vietnam. The step-by-step is in Vietnam eSIM activation, including what to do if the first connection fails.
For iPhone users, the dual-SIM setup (home line for calls, Vietnam eSIM for data) is covered in Vietnam eSIM for iPhone.
If something goes wrong
Most first-connection problems are one of three things: the eSIM is installed but not selected as the data line, mobile data is off for that line, or the phone is still locked to the home carrier. The help centre walks through each. If you bought a physical SIM and it stops working, take it back to the shop with your passport — carrier shops can check the plan status on the spot.
The short version
For most travellers to Hanoi, an eSIM installed before departure is the least friction. If you want a local number or you are staying longer, a carrier shop in the city is the better value. Either way, check compatibility first and know how much data you actually need.