Vietnam

Basics
There are 4 major GSM network operators in Vietnam: Two further providers are not on the list as Gmobile (formerly Beeline) is on 2G only and S-Fone on incompatible CDMA standard.
 * Viettel
 * Vinaphone
 * Mobifone
 * Vietnamobile

Coverage and speeds are quite good for SE Asian standards: 2G/GSM is on 900 and 1800 MHz, 3G on 2100 MHz. Viettel and Vinaphone introduced DC-HSPA in 2014, 4G/LTE has not started yet, but is expected to launch in 2016.

In March 2015, a new numbering plan was introduced and all 11-digit mobile numbers will be shortened to 10 digits. As prices are more or less ruled by the state, there is in fact not much competition going on between the operators and rates are pretty much the same amongst them.

To buy a prepaid SIM card, you have to officially show your ID or passport and need to be registered, before the SIM card can be activated. But in practice, this is not really enforced. You don't need to look for branded stores of the operators, but get them at many street outlets and other stores that double as SIM sellers. Just look for a sign saying 'SIM card' or an operator's name. There, they sell SIM cards that are already activated. These cards are new and never used before, but the shops already register them under someone's fake name, so that they don't have to register or take any actions at the time they sell the SIM cards to you. This scheme is still supposed to be safe.

When setting up, better check balance and validity as well as data, if you have bought a package to avoid getting cheated.

Viettel
Viettel is owned by the Ministry of Defence and thus the Vietnamese army. It's the market leader in Vietnam with about 40% of all customers on its network. It has the best coverage in remote places even on 3G. As prices don't differ so much between the 3 major operators, Viettel should be your first choice when you are going to rural areas.

Availability
SIM cards are available at the airports and lots of shops in town. Recharge cards are widely available in small shops and on the sidewalks. Shop staff is usually happy to try to help when adding credit, even if they don't speak a word of English. Best option is to visit a Viettel store in a bigger city. They speak good English and prepare everything for you, even cutting to nano sim. SIM cards are around 50,000 VND with some credit. Their regular prepaid brand is called Tomato and doesn't come with data. So you have to book a package. Balance check is *101# for main account and *102# for bonus account. To top up by voucher, type *100*# and. The vouchers can be aquired all around town, just look for the Viettel logo.

Data feature packages
Data on 3G is up to 21.2/5.76 Mbps. You may need to activate 3G data by texting "3G ON" to 161. Type *101# to check your call balance. Default rate outside of packages is 75 VND per 50 KB by default. In the big Viettel stores they can offer you big packages like 20GB for ~200.000 VND. These monthly packages can be booked: The first two packs are hard-capped, overuse is charged by 25 VND per 50 KB. The last 5 packages are soft-capped and speed will be throttled when reached quota. To subscribe, text activation code with blank in between to 9123 for free. All packages auto-renew, if there is credit. To stop, text "HUY" to 191, but all packages will be cancelled immediately and the rest of your data volume will be lost.

Some larger packages can be extended by add-ons giving you more data volume at high speed: This additional data is only valid during the monthly cycle of the prepaid package you are on and will expire if not used. You can check your current data balance by sending the text "KTMI" or "KTTK" to 191
 * 100 MB: 10,000 VND, activation: text "Max10" to 109
 * 300 MB: 20,000 VND, activation: text "Max20" to 109
 * 500 MB: 30,000 VND, activation, text "Max30" to 109

Tourist SIM
Viettel introduced a tourist SIM for visitors sold mostly at the airports and their big stores. It's sold for US$ 5 or 10 and needs to be added with one of these plans: International calls are to 25 countries only. Data overage charge is 9.76 VND per 50 KB.

Data-only SIM: Dcom
Their Dcom service is for Mobile Broadband in 3G: data-only for any devices. It can be used in smartphones too, but doesn't have voice and text. SIM cards can be switched from/to Tomato, but rates are very similar and you should think twice about losing text and voice capability. They sell these monthly data bundles for Dcom only:
 * DC5: 5,000 VND, 1 GB, for 24 hours only*
 * D10: 10,000 VND, 3GB for 24 hours only*
 * DC10: 10,000 VND, 50 MB
 * DC30: 30,000 VND, 200 MB
 * DC50: 50,000 VND, 400 MB
 * DC70: 70,000 VND, 600 MB
 * DC120: 120,000 VND, 1.5 GB
 * DC200: 200,000 VND, 3 GB

*Both packages will renew every 24 hours until out of credit.
All packages are for 30 days, but DC5 which is for 1 day only. DC10 is the default package, when no other bundle is booked. DC10, DC30 and DC50 are hard-capped with 9.76 VND per MB overuse fee. DC70, DC120 and DC200 are soft-capped and throttled when having reached volume. To activate, text the name of the bundle to 191. All bundles auto-renew. To stop text "HUY" to 191.

More info

 * APN: v-internet
 * Personal Hotspot (for iPhone tethering) APN: v-internetts
 * when starting up, the default PIN code will be 1111.
 * be aware that Viettel sends a lot of advertising SMS
 * Tourist Card on Viettel website: Tourist Card info

Vinaphone
Vinaphone is the 2nd operator in Vietnam. It is owned be the governement through the Vietnam Posts and Telecommunications Group. It has a market share of 30% and is local partner of Vodafone. It gives a good coverage and speed throughout the country.

Availability
SIM cards are widely available in shops and street kiosks where you see their logo for around 50,000 VND. Top-ups from 5,000 VND to 500,000 extend SIM life 1 to 215 days available at the same stores. To top up, type *100*#. There are different stater packs called VinaCard or similar. It doesn't make a difference which you choose for data as all have the same data packs.

Data feature packages
You may need to activate data first by texting "GPRS ON" to 888. Speed on 3G is a max. of 14.4 Mbps. Default data rate outside of packages is 1.5 VND per KB. You can book these monthly packages: Hard-capped packages will charge for overuse 0.5 VND per KB. Soft-capped packages will throttle speed when reached data quota. To subscribe text "DK" to 888. All packages auto-renew. To stop text "HUY" to 888. To check data balance, text "DATA" to 888. All texts to 888 are free.

More info

 * APN: m3-world
 * Website mostly in English: http://vinaphone.com.vn

Mobifone
Mobifone is the 3rd provider in the country with 18% market share. In 2015 it's in the process of privatisation. Speeds and coverage may be good in the centers and around the coast but patchy in the mountains.

Availability
SIM cards are widely available in shops and street kiosks where you see their logo for 50,000 VND. Top-ups from 5,000 VND to 500,000 extend SIM life 1 to 215 days available at the same stores.There are different stater packs called MobiCard or similar. It doesn't make a difference which you choose for data as all have the same data packs.

Data feature packages
You may need to activate data first by texting "DATA ON" to 999. Speed on 3G is a max. of 7.2 Mbps. Default data rate outside of packages is 75 VND per 50 KB. Furthermore, you can book these monthly packages: Hard-capped packages will charge for overuse 25 VND per 50 KB. Soft-capped packages will throttle speed when reached data quota. To subscribe text "DK" to 999. All packages auto-renew. To stop text "HUY" to 999. To check data balance, text "HK DATA" to 999. All texts to 999 cost 200 VND per SMS.
 * daily package: 150 MB, 8.000 VND, hard-capped, activation code: D1

Tourist SIM
Like Viettel, Mobifone sells Tourist SIM cards called "Happy Tourist". They cost 250,000 VND and come in 2 plans: The data card can be topped up by 200,000 VND for 3 GB, 300,000 VND for 5 GB or 500,000 VND for 8 GB valid for 30 days. The voice and data card can be tooped up by 200,000 VND for 1.5 GB and 80,000 VND call credit, 300,000 VND for 3 GB and 100,000 VND call credit and 500,000 VND for 5 GB and 200,000 VND call credit all valid for 30 days.
 * Happy Tourist Data (no voice): credit: 3 GB for 30 days, overuse data rate: 9.77 VND per 50 KB
 * Happy Tourist Voice and Data: credit: 1.5 GB and 80.000 VND for 30 days, overuse data rate: 25 VND per 50 KB

More info

 * APN: m-wap
 * Website in English: http://www.mobifone.com.vn
 * to order Mobifone SIM cards online to be shipped abroad for a steep surcharge: www.vietsimcard.com

Vietnamobile
Vietnamobile is the smallest of the 4 providers. It is privately owned. It gives out the best prices in Vietnam, but their 3G coverage is very limited. It has a market share of around 10% and 3G only in Ho Chi Minh City, Da Nang, Hanoi and a few other places. So make a network scan before you buy a SIM card.

Availability
In the major towns you have to look for their logo to find an outlet first, as their English online store locator is not working. But, you can try your luck here: Starter kits come in different varieties. Their standard VMOne is for 25,000 VND with 10,000 credit, valid for 30 days. Other kits may be higher with more credit preloaded.

Top-ups are by scratch cards of 10,000, 20,000, 50,000 and 100,000 VND. You get a bonus of 100% for the first 10 recharges of 20k or higher.

Data feature package
You have to enable 3G data by typing *345#. Default rate outside of package is 75 VND per 15 KB. They offer these packages: Night offer: unlimted data 1am-7am within 7 nights for 10,000 VND. Activation: N10

To activate send text "DK" to 345. All plans auto-renew. To stop send "HUY"<blank to 345. All overuse is charged at the default rate.

More info

 * APN: internet
 * Website partly in English: http://www.vietnamobile.com.vn