Mobile providers and mobile internet in Thailand? [duplicate]

As Mark said there are DTAC, AIS and True Move. I'd go for True Move because they offer free wifi access across Bangkok. But if you're not in Bangkok then AIS would be the best coverage.

AIS > http://www.ais.co.th/12call/en/sim-card.html

DTAC > http://www.dtac.co.th/en/postpaid/products/ShortStayVisitors.html

True Move > I cannot find the information in English, but the information in Mark's webpage is quite accurate.

I suggest you go to big department store to buy simcard or at the airport because they can speak English. You can easily spot the sign AIS, True or Dtac. Also, you can get all the pre-paid sims at local 7-11 shops, but they might not be able to understand you. If you want to get the fun of being in a foreign country.

At the airport (luggage pickup) you will see a TrueMove-H stand (usually unmanned) with free SIM cards for travellers. They have a very small deposit on them also, but can be topped up at any 7-11 (millions of them!). These are also preset with important numbers such as tourist police and EMS services and immigration etc. They are also set to receive English script text. Thai SIM cards allow for English and Thai. Non Thai phones generally do not decode Thai so you get texts with little boxes instead of characters. They have a limited data account too, but will need to be topped up to use this. Activation instructions are in English.

Three main providers (DTAC/AIS/True) all have pretty much full coverage. 3G is limited by all of them to towns, flipping to Edge in the suburbs. There is no 4G everywhere in Thailand you are likely to travel to (maybe not in the middle of the rainforest!)

Rest assured which ever SIM you chose expect plenty of adverts by text!

Let me post my notes. Buying a DTAC SIM at the airport seemed to be the consensus of the information I googled. I wanted to post all my notes as I learned some things doing the top up:

I bought 4.5 gigs for 1 month for 549 (or 649?) baht at the airport. It included some call credit. The airport attendant put in the SIM and activated the service and made sure it is working, which is a good reason to buy it at the airport. I bought the DTAC SIM so the phone numbers I give below are probably specific to DTAC. The happy tourist sim includes a help card with some codes you need to check balances or activiate services (DTAC: check baht balance *101*9#, check balance of internet / everything else: *101*1*9#). To use a code, you type it in and dial after typing in the #. A response will show on your phone immediately, or you may receive a response as a text message.

Had I only bought the SIM without the internet service activated, I would need to add baht to it (a top up at 7-11) and then buy a package via call code at https://www.dtac.co.th/en/prepaid/products/happy-unlimited-internet-package.html. I do not use voice calls much, so rather than buy a package I let it charges bahts when I call. But you can find packages related to calling.

Later I did not have wifi in my hotel and my data needs went up. I used up the monthly 4.5gb and needed to top-up. I went to seven eleven and ask for a top-up, 200 baht. I typed my telephone number on a keypad they pointed at (starting with 0). So now my phone has 200 baht. You can call *101*9# to verify the top-up has affected your balance.

Next I used the charge to buy more internet data. But I couldn't buy another plan package (https://www.dtac.co.th/en/prepaid/products/happy-unlimited-internet-package.html) like I would in other countries (because the plan is still active), I had to buy "topping", with toppings listed here: https://www.dtac.co.th/en/prepaid/products/internet-speed-topping.html

Toppings extend the fast data limit for your monthly plan. But unfortunately, like your monthly plan, they are still active and cannot be replaced after you consume the fast data. So you can only buy one topping, which for me was quickly consumed when my phone decided to update everything.

So I needed another topping. After adding more baht at 7-11 is when I realized you could only buy one topping. So I called DTAC support at 1678. I told her I needed more data, she was able to close my previous topping and buy me a new on (2 gigs 7 days for 53 baht, and I could check the remaining data balance at *101*1*9#

Another note: At one store, when I bought top-up, they gave me a receipt rather than charing the phone directly. To charge up the phone, visit https://my.dtac.co.th/esv/en/quickRefill. The serial number is on the receipt. The ID number asked for is part of the PIN code on the receipt. For the ID number, take the last 6 digits of the PIN code.