The telephone country code for Thailand is 66 and is used when calling the country from abroad. All Thai telephone numbers are preceded by a ‘0’ if you’re dialling domestically (the ‘0’ is omitted when calling from overseas). After the initial ‘0’, the next three numbers represent the provincial area code, which is now integral to the telephone number. If the initial ‘0’ is followed by a '6', an ‘8’ or a '9' then you’re dialling a mobile phone.
If you want to call an international number from a telephone in Thailand, you must first dial an international access code plus the country code followed by the subscriber number.
In Thailand there are various international access codes charging different rates per minute. The standard direct-dial prefix is 001; it is operated by CAT and is considered to have the best sound quality. It connects to the largest number of countries, but it is also the most expensive. The next best is 007, a prefix operated by TOT with reliable quality and slightly cheaper rates. Economy rates are available through different carriers – do an internet search to determine promotion codes.
Inside Thailand all telephone numbers include an initial '0' plus the area code and the subscriber number. The only time you drop the initial '0' is when you’re calling from outside Thailand.
The easiest option is to acquire a mobile (cell) phone equipped with a local SIM card. Buying a prepaid SIM is as simple as finding a 7-Eleven. SIM cards include talk and data packages and you can add more funds with a prepaid reload card.
Thailand is on the GSM network. The main mobile phone providers include AIS (1 2 Call) (www.ais.co.th/12call/th), DTAC (www.dtac.co.th) and True Move (www.truemove.com), all of which operate on a 4G network. Coverage and quality of the different carriers varies from year to year based on network upgrades and capacity. Carriers usually sell talk-data packages based on usage amounts.