Pre-Paid Sim

You will need to register the sim using your ID, just go to one of the carriers shops or to a large phone store. Its very easy. They will set it up in English for you.

Expanding on Colinoscapee's answer:
First make sure that you arrive with an 'unlocked' phone meaning you have paid off your contract with AT+T and you are free of that network.

You can certainly get a sim and prepaid minutes at the airport arrival's lobby (on your way out of customs with your baggage.) Many people do that, it just might cost a few dollars more. If you can wait until you get to your hotel, you can save some money and maybe a long line. While in the airport there is free wifi.

In the lobby, you will have your first opportunity to pull out some Vietnamese currency with your ATM card. You will need that for the taxi or whatever.

Your hotel can direct you to a shop for the sim. There are several carriers. It probably doesn't matter which. The process is simple, no paperwork. Show them your passport to register. A Mobi sim card cost me  a one time charge 100.000 ($5). Then you will need a month of minutes. That will be 75.000 or 100.000 for several gigs of data, phone, and texting. Every month on the same day you can get a new charge at any 7-11 type store or carts on the street.

Enter the password to turn on your phone, the seller will install your sim for you, and enter the code for your minutes. (Save your old sim, it is tiny! Also pack a paperclip that you can use to open the sim door when you go home.) Make sure you test the internet works and phone works. When you need a monthly recharge, the convenience store clerk can enter the code for you, or someone can show you how that works.

So can I re-use my SIM card that I got when I was in VN 2 years ago and just buy the data for it or do i need to start with another new SIM card?

qnbui wrote:

So can I re-use my SIM card that I got when I was in VN 2 years ago and just buy the data for it or do i need to start with another new SIM card?

All legal SIM cards will be blocked after one year at the latest if they are inactive or are not periodically recharged.

During the runtime you can check the expiration date (e.g.*102#).

AkaMaverick wrote:

All legal SIM cards will be blocked after one year at the latest if they are inactive or are not periodically recharged.

During the runtime you can check the expiration date (e.g.*102#).

Thanks for the info!

One more piece of information:

In the past you had to have access to the telephone net to recharge your SIM card. Or you had to use a service like "Ding".

Nowadays it is partly possible to charge or manage your SIM card via the phone app without the SIM card being in the phone.
So you can always check the expiration date and extend it by loading a little money on the SIM card (But for the first app setup you must be in the country of the SIM card phone company).

With the Thai "dtac" this works well. You have to load about 2 Baht per month extension.

With the Vinsphone app you can now also log in via WiFi.

You have to find out for yourself if this works for your SIM card.

gobot wrote:

Expanding on Colinoscapee's answer:
First make sure that you arrive with an 'unlocked' phone meaning you have paid off your contract with AT+T and you are free of that network.

I wanted to ask about this.  My current phone is a company phone from my company in the US under Verizon.  Whenever I come to Vietnam I just swap in my VN SIM.  When I go back to the US I swap out my VN SIM for my US SIM and it goes back to being active.

Is this because my company is still paying the bill when I am gone and it's paid current and still active?  I've never paid off my contact and am not free of that network.  I didn't do anything to unlock the phone or anything.  It's not a jailbroke phone or anything special, just a normal I-phone 8.

AkaMaverick wrote:

qnbui wrote:

So can I re-use my SIM card that I got when I was in VN 2 years ago and just buy the data for it or do i need to start with another new SIM card?

All legal SIM cards will be blocked after one year at the latest if they are inactive or are not periodically recharged.

During the runtime you can check the expiration date (e.g.*102#).

If you want to use same SIM (same number) when you return to Vietnam, ensure that you top-up sufficiently before leaving vietnam. Maybe 100k/200k VND . Check expiration of SIM (for viettel I use *101#), make a reminder on your calender/diary for 3 days before expiry, then when you see reminder send an sms to a friend/yourself to extend expiry.

I've been doing this with my current Vietnamese Viettel SIM (phone number).  BTW, the country you leave to must be a roaming country (with viettel many countries are 'roamable', but ensure you enable roaming before leaving vietnam, otherwise you have to contact support to enable - can be a hastle).

If you forget to do the above, there is a small chance that you can  reclaim your phone number by visiting a viettel store, but only if the number hasn't been allocated to someone else. I have experience with both. i.e. Once I paid about 25k VND to get same number, the other time (with different SIM) I lost number because it was already allocated to someone - that time I was told by Viettel staff member at shop that there is a package that I could have bought before leaving vietnam that would have made the SIM a 'long expiry' SIM. I forget what the package is but he said it cost about 50k VND.