Legitimation, Custody and Adoption Records

Under the Civil and Commercial Code a child born to unmarried parents is always the lawful child of the mother, who exercises parental power. The father becomes the lawful father only by marrying the mother, by registering legitimation, or by court judgment.

Registration of legitimation (Kor Ror 11) requires the consent of both the child and the mother given before the registrar. Where the child is too young to consent, or the mother does not or cannot consent, the father must petition the court and then register the court order at the registration office.

Once the child is a lawful child, the child is a statutory heir of the first class of the father under Book VI of the Civil and Commercial Code, with the same rights as a child born in wedlock. It also affects maintenance duties and the use of the father's surname.

An adoption becomes complete on registration at the district or local registration office, following approval under the Child Adoption Act by the Department of Children and Youth. Where the adopter is a foreign national, a probationary care period and additional vetting apply, so the timeline is longer than for Thai adopters.

The Nationality Act B.E. 2508 gives Thai nationality by birth to a person born of a Thai father or a Thai mother, whether inside or outside the Kingdom. Where a Thai father was not married to the mother, evidence of legal paternity — legitimation or DNA evidence as the agency requires — may be needed.

Many civil registration tasks, such as requesting certified copies, can be handled under a power of attorney with signed copies of both parties' ID cards. Matters requiring personal declaration of intent or biometric capture — ID card issuance, marriage registration and legitimation — must be done in person.

Typically the adoption registration, the approval or order from the responsible authority, the birth certificate and a house registration showing the relationship, all translated with the translations legalised. Some countries add certification at their embassy in Thailand, so request the document list in writing first.