Thai children under 18 now need a birth certificate to fly out, and often a consent letter

The Immigration Bureau said on 4 November 2026 that any adult leaving the country with a Thai child under 18 must prove how they are related. Officers ask for the child's passport and birth certificate; an original, a photocopy or a photo of it on a phone are all accepted. The rule follows nationality, so it also covers children with one foreign parent.

A parent flying out alone with the child, including a foreign or a divorced parent, needs a consent letter from the other parent. A legal guardian carries a copy of the court order. Anyone else needs consent from both parents or the guardian. Each letter has to be signed in front of an official at a district office or an embassy and is valid for 60 days at most; school trips can use a letter from the school instead.

The bureau said it turned back 32 departures between July and October 2026, which it linked to networks registering Chinese children under false Thai fathers. The check extends a birth-certificate requirement that Suvarnabhumi's departure immigration started enforcing over the summer.