Forgot to Fill the TDAC Before Your Flight? What To Do

General information only

This guide is information, not legal or immigration advice. Rules change, so confirm on the official government site before you travel.

You are at the airport, or already in the air, and you remember you never filled in the Thailand Digital Arrival Card. This is common and usually fixable if you act calmly and use only the official site.

Short answer

The TDAC is meant to be submitted within the 3 days before arrival, counting arrival day. Travel guides report that if you forgot, you can still complete it on your phone with an internet connection, even on arrival before you join the immigration line. Do not rely on this as a plan, because airline check-in staff may ask for the confirmation before boarding.

What to do, step by step

Open the official TDAC site from the button on our Thailand page.
Have your passport, flight details and first Thailand address ready.
Fill in the form. Copy the passport details exactly.
Save the confirmation or QR code as a screenshot.
If you cannot get online, ask airline staff or airport help desks what they can do, and keep your documents ready.

If you are still at home or at check-in

Do it now, before you leave. It takes a few minutes on a phone, and it removes the risk of being stopped at check-in. Many airlines check documents before they let you board, and an arrival card is part of that picture.

What not to do

Do not pay a "fast approval" or "urgent TDAC" site. The official form is free and approval is instant.
Do not submit before your window opens. The official system only accepts the allowed dates.
Do not guess details. A wrong passport number is worse than a short delay.

Questions and answers

Can I fill the TDAC at the airport?

Travel guides report you can submit it on a phone or tablet with internet before you reach the immigration line, but do not depend on this. Airlines may ask for it at check-in.

Is there a penalty for forgetting the TDAC?

We could not confirm a fixed penalty on the official portal. The practical risk is delay at check-in or immigration, so submit as early as the window allows.

Can I submit more than 3 days early?

The official system accepts submissions within the 3-day window. Some third-party services offer early filing for a fee, but you do not need to pay for that.

Sources

Facts were read in these sources on 2026-11-01. Where a source is a news report or travel guide and not the official site, we say "reported". Always confirm on the official portal.

Shahzaib Chauhan
Published Nov 1, 2026 · Updated Nov 1, 2026 · How we check facts

Forgot the TDAC Before Your Flight?What To Do Right Now