You can apply for Thai citizenship if you are working in Thailand or are married with a Thai spouse and/or have a child born in Thailand.
In all cases you will also have to fulfil the following conditions to apply for Thai citizenship:
- You must have lived in Thailand continuously, for at least five years before applying.
- Be a permanent resident.
- Be 18 years old or older and have reached legal majority in your country of origin.
- Be well behaved and have a good background (criminal record; political background; involvement with illegal drugs and, in the case of Vietnamese applicants, personal behaviour will be checked).
- Know the Thai language, including speaking, listening and understanding.
- Be able to sing the National Anthem Sanserm Phra Baramee and pass an interview in Thai conducted by government officers.
Citizen of western countries (i.e. US, UK, Canada, Australia, France) can have dual citizenship in most cases (e.g. Thai citizenship and their original nationality).
Once your application for Thai citizenship has been approved, there will be a lot of waiting. You will be asked to appear at the Interior Ministry for a Thai language test. If you pass the test you will be asked to come back to the Thai Ministry and sing the Thai National Anthem and the King´s song Phra Baramee. Afterwords you will be interviewed while the Thai officials visit your house to ascertain that the details you submitted on your application form are correct.
Among the others requirements, you will be expected to swear an oath and appear at your local police station dressed well and holding a candle, flowers and incense. You will have to swear allegiance to the King and to the country of Thailand. This, however, is not the end as you will then have to wait for a confirmation by the Ministry of the Interior that your Thai citizenship has been awarded.