[Guide] Select or change your Mobile Network Operator

One of the first thing you might do when you arrive in Vietnam is to purchase a simcard and register for a data package (3G/4G).

### Overall choice
There are mostly 4 Mobile Network provider in Vietnam:
- Viettel
- Mobifone
- Vinaphone
- Vietnamobile

You can buy a simcard at airport, on the street (Small shops) or directly to an official store (Recommended).
The registration is quite simple and you will need to provide some information (Need your passport)
You will have 2 options either pre-paid (Most popular, you top up and you use), or post-paid.

Top up can be done quite easily, either to go directly at the store, or at convenience store (7-11,..) or directly with several apps (Grab,...) or bank services (Timo). I usually prefer to use my bank service or Grab, as it takes 1min to do it and you keep the record.

### Select your provider
I will not discuss much about the cost, as it is relatively low in Vietnam and can greatly fluctuate based on their promotions. Let me discuss more on the quality of service.

All those operators are improving their network coverage and speed and it won't be accurate to simply share the general feeling of each providers (We usually said that Viettel is having a better coverage than the others, etc..). I rather share more statistics on this, as it will depends on what you want, where you are, etc...
I personally use NPERF to gain insight on this. Nperf is a community based platform that assess the coverage and speed of network providers, with real speed test and coverage mapping.
Nperf map for Vietnam
You can select the provider and check the coverage map of 3G, 4G and even 4G+ (LTE), you can also check the speed.

If I take the example of HCMC, we can see that:
- Viettel: Got 4G everywhere and many 4G+ record  |   The speed of 4G looks decent with some higher values as well (4G+ probably)
- Mobifone: Got 4G everywhere but probably no 4G+  |  The speed of 4G looks not so good
- Vinaphone: Got 4G everywhere but no 4G+   |   Yet the speed of 4G looks decent
- Vietnamobile: Got 4G everywhere and some spot of 4G+  |   Yet the speed looks bad.

You could check this for all Vietnam, as long as individuals are reporting their speed / coverage. (Community-based)

I'm personally using Mobifone, and I can confirm those info. Obviously this is changing fast and will depends on your location, where you go, etc...

### Packages
All those providers are providing a various choice of communication and data plans.
I always found it complicated... you have SMS or Tel plans, data plans, different period (1 month data, 3 months data, 6 months data,..). In some cases it's a one time shot plan or some will be auto renewed.
As it changed quite frequently, I suggest you to check directly the provider that interest you:

Viettel Plans
Mobifone Plans
Vinaphone Plans
Vietnamobile Plans


### Change provider
Recently, Vietnam has implemented the Mobile Number Portability (MNP), meaning you can change operator but keep your number. (Finally!).
You simply need to go to the official store to implement it. You will have a small fee (60k VND) and they will guide you in the process.
An important point, the sim card needs to be under your name as you will need to provide your passport or resident card, and your contract with the previous provider needs to be at least 6 months old (To avoid people changing provider too frequently).
You can get those info (Sim card owner and subscription date) by sending the message TTTB at 1414.
Note that changing the owner (Many Sim cards used to be declared under a different name to ease the process for foreigner) will reset the contract period (You will need to wait 6 months  again)

Hope those info can help you.