All persons, other than those in transit and citizens of certain countries, are required to obtain a visa in order to enter Thailand. Foreign nationals who intend to remain in Thailand to work or conduct business must comply with visa requirements in addition to obtaining a work permit prior to starting work in Thailand.

The Immigration Act, B.E. 2522 establishes the following visa categories:
• Transit Visa
• Tourist Visa
• Non-Immigrant Visa
• Diplomatic Visa
• Official Visa
• Courtesy Visa