Most foreigners who intend to work in Thailand are subject to the Alien Employment Act B.E. 2521 (A.D. 1978). Under the provisions of this Act, a foreigner cannot perform any act of work or service unless a work permit has been issued by the Department of Employment, Ministry of Labor and Social Welfare, or unless the individual, or the work performed, falls within an exception to the Act.
                           The term "work" is defined very broadly, i.e. "working by exerting one's physical energy or employing one's knowledge, whether or not for wages or other benefits". Theoretically, even volunteer or charity work requires a work permit. Although they receive no remuneration for the work performed, volunteer teachers have been required to obtain work permits.
Visiting speakers at seminars and conferences, whether or not receiving remuneration for their services, presently do not need work permits. However, except in cases where a government agency or state enterprise is a co-organizer, the Department of Employment must be informed before the seminar or conference is held.
                           An applicant for a work permit must have either a non-immigrant visa or a residence permit. Generally, a non-immigrant visa must be obtained before entering Thailand. A residence permit is usually issued only after a foreigner has resided in Thailand for a number of years under a non-immigrant visa.
                           An employer or potential employer may file an application for advance permission for an employee to work before the foreigner enters the country. However, the work permit itself will not be issued until the individual enters Thailand on a valid non-immigrant visa.
                           Regardless of the length of time approved in the work permit, it is valid only as long as the foreigner's visa permits him to remain in Thailand. Also, a work permit is good only for the particular job for which it was issued and within the geographic limitations specified in the work permit. Foreigners may hold more than one position with one or more employers but must obtain permission for each position and for each employer. Generally, the permission for each position is entered in the original work permit record.
                           Exceptions to the Alien Employment Act permit foreigners to perform work deemed necessary and urgent which can be completed within 15 days. However, the Department of Employment must be informed before work begins.

                           Certain foreigners are exempt from work permit requirements. There are seven categories:
                           1. Members of the diplomatic corps;
                           2. Members of a consular mission;
                           3. Representatives and officials of the United Nations and its specialized agencies;
                           4. Personal servants from abroad employed by any of the above;
                           5. Persons who perform duties or missions under agreement between the government of Thailand and another                                foreign government or international organization;
                           6. Persons who perform duties or missions for the benefit of education, culture, arts, sports or other activities as                                may be sanctioned by royal decree;
                           7. Persons with special permission from the government of Thailand to enter and perform duties or missions in the                                Kingdom.

                           There are 39 occupations reserved for Thais which are closed to foreigners. These include labor work; agriculture, animal husbandry, forestry or fishery; carpentry; shop attendance; accountancy; haircutting and hairdressing; civil engineering; architectural work; dressmaking; clerical or secretarial work; and legal service, among others.
                           Penalties for working without a work permit or doing work not specified in one's permit include imprisonment notexceeding three months or a fine of up to Baht 5,000, or both. People who do work reserved solely for Thais are liable toimprisonment of up to five years or to a fine from Baht 2,000 to Baht 100,000, or both.

WARNING
                            Please note that this information is not inclusive of all the answers to questions involving work permits and related matters but is intended to address general issues. Whenever appropriate, please consult a lawyer versed in labor matters or the nearest Department of Employment official. Policies and procedures may change rapidly and without notice.