If you travel through or live in Thailand for any significant period of time, chances are that you have a local SIM card for your phone. One of the most popular networks is One-2-Call from AIS. They have great coverage. I nearly always have phone signal and EDGE internet whether I am in the remote North-east of Thailand or on a tiny island in the South.

Now… One-2-Call do not publicise this very well, but it is possible to get unlimited EDGE and GPRS data for a monthly fee of 650 baht (approx $20) on your prepay sim card. Also a lesser known fact amongst casual users, is that you can use their online service to switch your calling plans, add SMS bundles, transfer balances, add special numbers and a variety of other goodies.

While this guide is all about the unlimited data option, you can also select lower cost hourly packages 20 hours (100 baht), 100 hours (350 baht) etc. However, if you are an iPhone user and Facebook/Twitter addict like me, then you’ll want your phone online permanently.

How to activate unlimited data

STEP 1) Make sure you have the relevant amount of credit available on your phone (i.e. at least 650 baht) and then visit https://12calleservice.ais.co.th/EPPWeb/index.html to access the eService. You can switch the language between Thai and English in the top right corner.

STEP 2) Enter your phone number. The system will then send you a one-time password via SMS to access the eService website. This password is valid for 15 mins. Once you receive your password you can proceed to login. Once you are in, you can view your call plan, value added services, remaining credit, validity period etc. Have a good browse because there are a load of goodies you can play with. I won’t go into it all in detail here.

STEP 3) In the left hand menu, select the option:  Call plans > Call plan & value added service switch/signup. Once in this section, you can select a whole host of promotions, call plans, bolt-ons etc. The option we are after is under the tab “Value added service”. Select option 7 – “GPRS Package 650 Baht Monthly fee 650 Baht, You can use free EDGE/GPRS Unlimited”, and then click OK at the bottom of the page.

STEP 4) You will then be taken to a confirmation screen. Click OK and you should be good to go. Assuming you have 650 baht available on your phone, your credit will be charged and you should receive a confirmation SMS.

Check your data usage

To check your remaining EDGE/GPRS usage, along with remaining SMS, MMS and other bolt on packages you might have added to your account, you can dial *139# SEND. Here is the response on my iPhone. Notice the lovely, juicy UNLIMITED text beside the EDGE/GPRS. Happy days.

If you find this guide useful, please help me by retweeting it and linking to it from your blogs. I would also love to hear any comments or additional tips you might have.