Sim, eSIM and internet when you first arrive abroad

🔄 Cập nhật lần cuối: 08/10/26

The moment the plane lands, the first thing most international students want to do is text "I've arrived" to their parents. Preparing a sim card, eSIM to study abroad and an internet plan in advance helps you to contact immediately, call a car, open a map and receive an authentication code without having to struggle to find wifi. This article summarizes popular options, advantages and disadvantages, and notes about Vietnamese SIM cards that many of you ignore.

Check your phone before flying

Before thinking about which SIM to buy, make sure your phone can be used abroad:

• The device is not locked to the network (unlocked): universities in Australia such as Macquarie University remind international students to check this before coming. The device is "locked" according to the network and will not accept another SIM.
• Does the device support eSIM: go to mobile settings, if there is an "Add eSIM" section, it's ok. Some models sold in some markets do not support eSIM or only support one SIM.
• Band: Newer devices are often compatible with 4G/5G networks in most countries, but too old devices may have poor signal reception.
• Charger and adapter: bring a spare charger (put it in your carry-on baggage) and a socket adapter suitable for the destination country.

If you're making a list of things to bring, see this article Study abroad luggage: list of things to bring so as not to forget the power bank - the item cannot be placed in checked baggage.

Compare sim, eSIM and ways to get internet when you land

There are four main options. Many people combine the two options to both have an immediate network and save money in the long run.

How to install eSIM at the right time

1. Buy an eSIM package from a reputable supplier, carefully read the capacity, term and coverage area.
2. Scan the QR code to install while still in Vietnam (internet required to download eSIM profile), but only turn on "mobile data" for eSIM when you land, depending on the activation conditions of each package.
3. Set eSIM as the main data line, keep the Vietnam SIM as the call/SMS line and turn off data roaming of the Vietnam SIM to avoid incurring charges.

Buy local SIM: prepaid or contract

Local phone numbers are almost mandatory open a bank account, register with a doctor, go to a part-time job or receive a call from the landlord. There are two main forms:

• Prepaid: buy sim card at supermarkets, convenience stores or network stores, top up monthly, no obligations. This is a reasonable choice in the first month.
• Contract (postpaid/plan): usually 12–24 months, may include device, but incurs fees if canceled early and often requires credit history or residence card.

Varies by country

In Australia, UK, USA, Canada, prepaid SIM cards are quite easy to buy with just your passport. In Japan and Korea, registering for a long-term subscription often requires a residence card (alien card), which is only available after entering the country and registering an address, so a temporary eSIM/sim data for the first week is essential. Many universities give out free SIM cards or introduce network operators during orientation sessions - see more articles First day of school and things to do.

Keep your Vietnamese SIM card to receive OTP and authenticate your subscription

Don't rush to give up your Vietnamese SIM card. This phone number is associated with bank accounts, e-wallets, VNeID and many important services.

• Bank OTP: if your bank sends OTP via SMS, you need to register for international roaming to receive the news. Many banks now use Smart OTP on the app - switch to this method before flying to not rely on SMS.
• Authenticate subscriber information: according to current regulations on standardization of subscriber information, the subscriber needs to authenticate with a chip-mounted CCCD. People abroad can do it through the network operator's application (need a phone with NFC, CCCD and an OTP number). It's best to complete before flying.
• Maintain subscription: Prepaid SIM cards that do not generate transactions for a long time may be revoked. Find out about your carrier's maintenance plan or switch to postpaid.

You should also set the phone's date and time to automatic mode so that the banking application does not authenticate errors when changing time zones.

Contact your family in the early days

Please agree with your parents on the shared messaging application (Zalo, Messenger, WhatsApp...) and appropriate calling hours time zone difference. Once you have a local number, send the new number to your family and the person picking you up. If you're flying in transit, it's a good idea to have a network at the transit airport to update when your flight is delayed – regional eSIM plans often cover multiple countries.

For customers booking tickets through VeDuHoc, parents are notified of flight status via Zalo and the 24/7 support team, so they can still understand the itinerary even when their children don't have internet connection yet - see how it works in the article. Parents track flights via Zalo. Tools for keeping long-term connections are summarized in the article Keep in touch with family while studying abroad, and the preparation for airport pick-up is in the article Airport pick up and accommodation for the first days.

Frequently asked questions

Should I buy an eSIM first or wait until next year to buy a SIM?

You should have an eSIM or data roaming package for the first few days to get internet as soon as you land, then buy a prepaid local SIM card once you're stable.

Can dual sim phones use both Vietnamese and local sims?

Yes, if the device supports two SIMs (physical + eSIM or two slots). You leave the local SIM for data, the Vietnamese SIM only receives calls/SMS.

Can I receive OTP without roaming enabled?

Usually no with OTP via SMS. Please switch to Smart OTP or register for roaming before flying; Ask your bank to know exactly.

Is free wifi at the airport safe?

Can be used for texting and looking up maps, but limited banking login on public networks.

Good communication preparation makes the first trip easier for both children and parents. If you are planning a flight, consult the service air tickets to study abroad or contact hotline/Zalo 090.1800.918 for advice on a suitable schedule.

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