I'll be traveling to SE Asia, and want one phone service. If I buy a SIM card with Viettel in Vietnam, will it function in Thailand and in Laos and in Cambodia?

If it does, will I be charged roaming?

4 Answers 4


Yes and yes. There are no universal SIM cards in SE Asia, they all charge roaming fees, which can be quite expensive. It is much easier and more economical to get a pre-paid SIM card in each country as you travel. Or use voip services through your hotel's wifi each night.

  • This answer is outdated and may have been incorrect at the time of writing.
    – Willeke
    Jan 6 at 8:26

As of 2017-01-11 Yes and partial yes.

There are no universal SIM cards in SE Asia.

However, from 2017-01-01, Viettel removed reduced roaming charge in Vietnam, Laos, Cambodia.

Source: http://vneconomictimes.com/article/business/viettel-to-scrap-mobile-roaming-charges

The new fee can be found here (unfortunately it's in Vietnamese) in tab "Cước Roaming Đông Dương".

The new fee is:

  • 2000 VND/min (my normal charge is 1380 VND/min) for calling between Viettel, Metfone (Cambodia), Unitel (Laos),
  • 7260 VND/min to call to other operators in the roaming country.
  • 27500VND/min to call to other operators in the home country.
  • 500 VND/sms (compare to normal 290/350 VND/sms) between Viettel, Metfone (Cambodia), Unitel (Laos)
  • 4840 VND/sms to other operators.
  • free to receive call/sms
  • 2 VND/10KiB Data (the normal data charge inside Viet Nam is 75VND/50KiB if you don't buy an extra data package)
  • Great information - do you know whether this applies to data packages, which I think will be most useful for travellers? All I can get from Google Translate on some Vietnamese articles is something to do with 200,000 VND/GB, which seems a little higher than normal (but not outrageously so).
    – EdC
    Jan 11, 2017 at 5:28
  • @EdC I think 200,000 VND/GB is a little higher than normal if you normally by an extra data package (most of people buy it, btw). The normal rate for data in Vietnam is about 75VND/50KiB if you don't buy an extra package.
    – Danh
    Jan 11, 2017 at 6:24

As of 2024 you can get an eSIM from Airalo or another virtual operator that covers all 4 countries for a reasonable price. Airalo currently lists an "Asia eSIM" where you get 5GB for $20, covering 14 countries in the region.

Disclaimer: I'm not affiliated with Airalo or eSimDB. I've used Airalo before but I'm not paid by them.


I have been using since 2013, thereabouts, SIM cards by China Unicom HK that are valid in a selection of countries. So answers around 2016 saying There are no universal SIM cards in SE Asia were already incorrect.

China Unicom 【Southeast Asia】8 Days unlimited data

China Unicom Asia 4G 30-Day 10GB DATA SIM Card

And today in 2024 it's even easier, with SIMs and eSIMs available from many providers.

Singapore, Malaysia and Thailand 7-Days Data Prepaid Card

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .