Glossary · Glossary of terms

Apostille

Quick answer: An apostille is a form of document authentication issued under the Hague Apostille Convention (1961) that certifies the authenticity of a public document (birth certificate, police clearance, marriage certificate, company documents) for use in another signatory country. Thailand is not yet a Hague Convention party: it acceded on 30 June 2026, but the Convention does not enter into force for Thailand until 28 February 2027 (HCCH status table, checked 14 August 2026). Until that date a document for use in Thailand needs the full consular legalisation chain, and an apostille alone will be refused. For Thai visa applications requiring certified foreign documents, the current route is therefore consular legalisation — the issuing country's authentication followed by legalisation at the Thai embassy or consulate there. From 28 February 2027 an apostille is expected to replace that chain. The issuing authority varies by country — in Australia it is DFAT; in the UK it is the FCDO; in the US it is the Secretary of State for the relevant state.

Guidance based on official sources; we confirm the current rule for your case.