To call Thailand: If you're calling Thailand from the United States:
1. Dial the international access code: 011.
2. Dial the country code: 66.
3. Dial the number. So the whole number you'd dial for Bangkok would be 011-66-2-000-0000.
Important Note: When making calls to Thailand, be sure to omit the "0" that appears before all phone numbers in this guide (thus you will dial only eight digits after the "66" country code). When calling within Thailand, you will need to add the two- or three-digit area code for the place you are calling, unless the number is a special four-digit hot line for an airline or tourist organization.
To make international calls: There are two ways to make international calls from Thailand -- first, by IDD, for which the access number is 001; second, by Voice over Internet Protocol (VoIP), for which access numbers are 007, 008, and 009. The latter are much cheaper. After dialing the international access number, dial the country code (U.S. or Canada 1, U.K. 44, Ireland 353, Australia 61, New Zealand 64). Next, you dial the area code and number. For example, if you wanted to call the British Embassy in Washington, D.C., you would dial 001-1-202-588-7800.
For directory assistance: Dial tel. 1133, or dial any hotel concierge or operator (even if you are not a guest, they can help).
Note that cellphones are referred to as "mobiles" or "handsets" in Thailand, which operates on the GSM system. If you have an unlocked phone, you can install a local, prepaid SIM card (sold at 7-Elevens and cellphone stores in Thailand). Show your phone to the salesperson; not all phones work on all networks. You'll get a local phone number -- and much, much lower calling rates than using international roaming (unless you have a special plan; do check). Unlocking an already locked phone can be complicated, but it can be done; just call your cellular operator and say you'll be going abroad for several months and want to use the phone with a local provider. In Thailand, head to Mah Boon Krong (MBK), near the National Stadium BTS in central Bangkok, for assistance with unlocking cellphones at any cellphone vendor.
For trips of more than a few weeks spent in one country, buying a local SIM card becomes economically attractive, as Thailand has a number of cheap prepaid phone systems operated by One-2-Call, True Move, and DTAC. For around 800B, you will be given a starter pack, which includes a SIM card, an instant Thai mobile phone number, plus some free calls. Call costs depend on the package you choose; some systems offer free off-peak messaging (SMS). With most plans, though, incoming calls are free.
Almost all hotels now offer Wi-Fi to their guests free of charge. It's also free in Starbucks, as it is in most corners of the planet.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.