Any foreigner who wishes to enter Thailand is required to obtain a visa from a Royal Thai Embassy or Royal Thai Consulate-General. Whereas, there are various type of visa to apply for and it is essential to obtain the correct visa type for your purpose of staying in Thailand.
The types of visa are as follows:
Diplomatic Visa
Courtesy Visa
Official Visa
Transit Visa
Tourist Visa
Long Stay O-A, O-X
Non-Immigrant Visa
to perform official duties (Category "F")
to conduct business / to work, attend business conferences, scuba diving courses, to teach, kick boxing courses (Muay Thai) and massage courses (Category "B")
to invest with the concurrence of the Thai Ministries and Government Departments concerned (Category "IM")
to invest or perform other activities relating to investment, subject to the provision of the established laws on investment promotion (Category "IB")
to study, to come on a work study tour or observation tour , to participate in projects or seminars , to attend a conference or training course , to study as a foreign Buddhist monk (Category "ED")
to work as a film-producer, journalist or reporter (Category "M") with permission from the Ministry of Foreign Affairs of Thailand.
to perform missionary work or other religious activities with the concurrence of the Thai Ministries or Government Departments concerned (Category "R")
to conduct scientific research or training or teaching in a research institute (Category "RS")
to undertake skilled work or to work as an expert or specialist (Category "EX")
other activities (Category "O") as follows: to stay with the family, to perform duties for the state enterprise or social welfare organizations, to be a sport coach as required by Thai Government, to be a contestant or witness for the judicial process.