All persons, other than those in transit and those eligible for a visa exemption, are required to obtain a visa in order to enter Thailand.

Passport holders from 48 countries (including the United States, Japan, most member states of the European Union, Canada, Australia, Malaysia, and Singapore) and one special administrative region, Hong Kong SAR traveling for tourism, are permitted to stay in the Thailand without a visa for a period not exceeding 30 days on each visit.

If a foreigner from these countries enters the Kingdom at an immigration checkpoint of a bordering country by any means except airplane, they will be allowed to stay only 15 days each time, except for: Malaysian nationals arriving from Malaysia and persons from United States, England, Canada, France, Germany, Italy and Japan, who will be allowed to stay 30 days each time.

Foreign nationals of the countries that have an agreement signed with Thailand shall be permitted to stay according to the period which is mutually agreed between them. Extensions of stay are normally granted for periods of 30 days at a time, but the total stay may not exceed 90 days within a six-month period, counting from the date of the first entry. Tourists from Brazil, Peru, Chile, Argentina, and the Republic of Korea may enter without a visa for 90 days.
In addition, APEC Business Travel Card (ABTC) holders (business persons from the countries/territories under the APEC organization) may enter without a visa for 90 days.
Foreigners beneficiating from a visa exemption must possess sufficient founds (cash 10,000 Baht per person and 20,000 Baht per family).

A person who is not eligible for the visa exemption must apply for a visa on arrival at Thailand immigration border check-points and international airports. Nationals of 21 countries (including China, Taiwan and India) can obtain a 15-day visa on arrival.

Foreigners entering with a visa exemption or with a visa on arrival cannot work in Thailand. To obtain a work permit they must convert their visa into a business visa.