Foreigners entering Thailand must hold a tourist visa. However, if they wish to stay in the country to work, they must convert the type of visa. It must be a tourist visa or transit visa only, and the current visa must be valid for more than 15 days in order to apply for change of visa type.

       The required documents for applying for or requesting change of visa type to perform duties or missions as a family member of a foreigner working in a company or partnership (Code O) are as follows:

1. Application form for change of visa type (TM.86 only for foreigners with tourist visa or transit visa) or application form for obtaining a visa (TM.87 only for Phor.15, Phor.30, Phor.Phor.30 and Phor.Phor.90, only for foreigners without a visa);
2. Copy of passport (with personal information, stamps of visas, entry stamps, and visa extension stamps (if any)), and a copy of the TM.6 departure card;
3. One photo, 4x6 cm or 2 inches;
4. Fee of 2,000 baht;
5. Copy of passport and work permit of the foreigner that the applicant wishes to reside with;
6. Certificate of juristic person registration with objectives;
7. VAT registration certificate;
8. List of shareholders;
9. Copy of proof of father, mother, child, marriage certificate or birth certificate (certified by the embassy of the foreigner located in Thailand and the Legal Affairs Division, tel. +66 2575 1056 etc. 9, Ministry of Foreign Affairs), or a certificate from the embassy, public agency, or consulate, which states that it is part of the household certificate from the Department of Diplomatic Protocol, Ministry of Foreign Affairs;
10. Copy of personal income tax return of Thai employees (PND.1) for the past 3 months, with names of all Thai employees;
11. Copy of the latest personal income tax return of the foreigner (PND91).
    
    

       The applicant must sign every page of their documents to certify them. The authorized director under the registration certificate or the managing partner must sign every page and every sheet of the company's or partnership’s documents and affix the company's or partnership’s seal. When submitting documents to obtain or change the type of visa, please bring all documents and submit all original documents to the competent officer for convenient and quick check and processing.

Source : Immigration Bureau
Tel : +66 2-572-8500