Persons who wish to apply for Thai citizenship under the Nationality Act B.E. 2508 (A.D. 1965) must be permanent residence holders for 5 continuous years, have reached the age of 45, and be able to speak and understand Thai.
An exception may be made to this rule if there is reasonable cause, such as marrying a Thai and having children born in Thailand or having studied in a local university/college as an undergraduate.
The applicant must make an application and submit various required documents to the Criminal Investigation Division Group I, Subdivision 3, Royal Thai Police Headquarters, Rama I Road, Bangkok. The official fee is Baht 5,000.
The processing takes 2 to 3 years. In the case of a minor child sponsored by a mother or father having Thai nationality, there must be evidence of both sponsorship and the child's birth. Likewise, a wife seeking Thai citizenship based on her husband's Thai nationality must submit evidence of the husband's nationality, the marriage, and a formal request for Thai citizenship.
Under the new provisions of the Thai Nationality Act (No. 2) B.E. 2535 (A.D. 1992), any person, whether born inside or outside Thailand, whose father or mother has Thai nationality, is entitled to register his/her Thai nationality at the local district office where he/she wants to have his/her name registered in a house registration. He/she must submit various required documents.
