There's many pre-paid SIM cards you can choose from. The best place to buy these are from the 7-11 stores, which seem to be everywhere in built up shopping / tourist areas. You can get top-up cards of 100, 200, and 300 baht (about 8 USD). If you text message international numbers you will run out of credit quickly - but it's still probably cheaper than global roaming with your provider from home. about 10 years ago
I suggest you buy them directly at the airport. 7-11 always sells top-up cards, but not all 7-11 stores sell pre-paid SIM cards. Just the prepaid SIM card costs 50 baht, and then you need to top it up.
1-2-call is the best choice if you plan to travel around Thailand, overall they have the best network connectivity. If you stay in BKK, every company will be fine. about 10 years agoAnswered by Somphon via Travellr.com