Thailand Joins the Hague Apostille Convention on February 28, 2027: What Changes, and What Doesn't Yet

Thailand deposited its accession to the Hague Apostille Convention on June 30, 2026, and the Convention enters into force for Thailand on February 28, 2027. The United States did not object. That date splits everything in two. US documents presented in Thailand before February 28, 2027 still need the old authentication and embassy legalization route. Documents presented on or after that date take an apostille.

Until February 28, 2027: nothing changes yet

Thailand is not accepting apostilles today. A US document going to Thailand now still goes through authentication, ending with legalization by the Royal Thai Embassy or a Thai consulate. Presenting an apostilled document in Thailand before the entry-into-force date risks refusal, because Thai authorities are not yet bound to accept it.

From February 28, 2027: the embassy step disappears

Once the Convention is in force between Thailand and the United States, a US document for Thailand needs an apostille and nothing after it. State-issued documents, such as birth and marriage certificates, are apostilled by the Secretary of State of the issuing state. Federal documents, such as FBI background checks, are apostilled by the U.S. Department of State. For US documents, the Royal Thai Embassy legalization step ends.

The documents this affects most

Thailand is one of the largest destinations we handle. The change matters most for Americans retiring in Thailand, marrying a Thai national, starting employment, or buying property. Those files typically involve FBI background checks, birth and marriage certificates, and income affidavits. Every one of them loses its longest step.

What if my document is already in process?

Documents legalized under the old route before the switch remain legalized documents. The Convention changes what is required going forward, not the validity of certifications already issued. The risky zone is timing: a document that will be presented in Thailand close to February 28, 2027 should be prepared for the rules in force on the day it is presented.

Questions we hear

Is Thailand a Hague member today?

Thailand has joined, but the Convention is not in force for Thailand until February 28, 2027. Until that date, the legalization route is the only one Thai authorities accept.

Can I use an apostille for a document I will present in Thailand after February 28, 2027?

Yes. From that date, Thai authorities accept US apostilles, and the embassy legalization step no longer applies to US documents.

Does this change anything for Thai documents coming to the US?

Yes, in the other direction. From February 28, 2027, Thai authorities will issue apostilles on Thai public documents for use in the United States and other member countries.

This post supersedes our earlier guide, USA Document Certification for Use in Thailand, which described the pre-accession process and has been updated to point here.

Sources: Hague Conference on Private International Law (HCCH), Status Table for the 1961 Apostille Convention. Last verified October 26, 2026.

Email me at jared@apostillellc.com or call 848-467-7740 to request my services or learn more.