Thailand is forever "fine tuning" its visa regulations. Rules continue to change, and you're best to either contact a Thai consulate or embassy or else consult with a specialist visa. Generally speaking, two main visas are available for travelers. The first is actually a "visa free" stay of 30 days, the second is a tourist visa valid for two months.
Both can be extended, for varying lengths, varying number of times and varying costs.
Thailand customs allows visitors to enter Thailand with personal effects, the value of which does not exceed 80,000 Baht, without paying import fees as long as: 1) the items are specifically for personal or professional use; 2) the amount of goods are reasonable; and 3) the items are not subject to restriction or prohibition.
There are restrictions on the amounts of alcohol and tobacco products; only the following amounts may be transported into Thailand under duty free regulations:
* 250 grams of cigars or smoking tobacco, or 200 cigarettes
* 1 litre of wine or liquor.
PROHIBITED AND RESTRICTED GOODS: The Thailand Customs Department is responsible for stemming the illegal transport of illicit drugs into and out of Thailand. Consequently, Thailand Customs officials do occasionally ask to search passengers’ bags. If you have nothing to declare, simply walk through the Green Channel, stopping only if asked to do so by a customs agent.
If you have goods to declare, you should hand a customs form to the Thailand Customs Department agent at the Red Channel marked “goods to declare”.
It should be noted that plants and animals, as well as products made from such, may be subject to restrictions and quarantine.