Authentication & Apostille for Thailand citizens in the United States — 2026

Authenticating documents means making U.S. documents legally valid in Thailand, or Thailand documents valid in the United States. The process depends on whether Thailand is a Hague Apostille Convention signatory.

Thailand consulates processing authentications

When do you need authentication?

You need authenticated documents to:

• Marry abroad (FBI background check, divorce decree)
• Work or study in Thailand (diplomas, academic transcripts)
• Conduct business (corporate documents, powers of attorney)
• Inherit property or settle legal affairs
• Adopt a child or claim citizenship by descent

Required documents

• Original U.S. document (vital records, court orders, FBI check, etc.)
• Notarization by a U.S. notary (if not from a government agency)
• Authentication by the Secretary of State of the issuing state
• Apostille (Hague Convention) or consular legalization (non-Hague)

The authentication chain

For Hague Convention countries (apostille):

1. Get the document notarized (if private)
2. Submit to Secretary of State for apostille
3. Done — apostille is recognized internationally

For non-Hague countries (consular legalization):

1. Get the document notarized (if private)
2. Authenticate at Secretary of State
3. Authenticate at U.S. Department of State (sometimes)
4. Legalize at the Thailand consulate

Costs and processing times

Consular legalization fee at Thailand consulates: typically $30-$100 per document. Total processing chain: 2-6 weeks.