Under Book V of the Civil and Commercial Code, a child born to unmarried parents is the legitimate child of the mother, and becomes the legitimate child of the father only if the parents later marry, if the father registers legitimation, or if a court gives judgment of paternity. Registering legitimation at a district registrar requires the consent of both the child and the mother. If either cannot or does not consent, the matter goes to the Juvenile and Family Court. Every foreign-issued document must be legalised in the country of issue and its translation certified before it can be used in Thailand.
| Governing law | Civil and Commercial Code, Book V, Title II (parent and child) |
|---|---|
| Default status of the child | A child of unmarried parents is the legitimate child of the mother |
| Routes to paternal legitimacy | Subsequent marriage of the parents, registration of legitimation by the father, or a court judgment of paternity |
| Registering office | A district (amphoe) or khet registrar office handling family registration, under the Department of Provincial Administration |
| Consent | Registration of legitimation requires the consent of the child and of the mother before the registrar |
| When consent is unavailable | A petition must be filed with the Juvenile and Family Court for a judgment in place of consent |
| Foreign documents | Must complete the issuing country’s legalisation chain, then be translated with the translation certified by the Department of Consular Affairs |
| Official fees and timing | Set by the receiving office and subject to change; confirm directly with the registrar or the court where the matter is filed |
Birth certificate of the child
Thai originals or certified extracts; foreign certificates must be legalised and the translation certified
Passport of the foreign father
Copy with a certified translation if the registrar requires one
Thai ID card and house registration of the mother
Originals together with copies
Evidence of the father’s marital status (if requested)
Issued by the home-country authority, legalised, translated and the translation certified
Court judgment or order (court route)
A court-certified copy for use in the registration record
Checked on 2026-08-04; requirements change, so confirm with the authority before filing.
The required documents and timing depend on the receiving office in each case. Contact our team to confirm the checklist before you file.