The 72-Hour Rule Explained
The TDAC submission window opens 72 hours (3 full days) before your scheduled arrival date in Thailand. You may submit at any point within this 72-hour window and on the day of arrival itself.
Example: If your flight lands in Bangkok on Friday the 14th at 11:00 AM:
- Earliest you can submit: Tuesday the 11th at 11:00 AM
- Latest you can submit: Friday the 14th (before immigration processing)
- After landing without TDAC: risk of entry delays
Your Timing Options – Full Comparison
| When to Submit | Recommended? | Risk Level | Notes |
|---|---|---|---|
| 3 days before arrival | ✓ Best | Zero risk | Maximum window; submit from home |
| 2 days before | ✓ Great | Zero risk | Plenty of time to fix errors |
| Day before departure | ✓ Good | Very low | Recommended minimum |
| Morning of departure | ⚠ Acceptable | Low | Complete before leaving for airport |
| At check-in counter | ⚠ Risky | Medium | Airlines check TDAC; slow airport WiFi |
| On the plane | ✗ Avoid | High | Limited/no WiFi; form may not load |
| After landing | ✗ Not available | Very high | Immigration delays; possible entry denial |
Can I Fill TDAC on the Same Day as My Flight?
Yes, same-day submission is technically allowed. However, completing it the same morning before leaving for the airport is the recommended minimum. Here's why earlier is safer:
- Airline check-in – airlines may verify TDAC at check-in; if you haven't submitted, you may be held up
- Technical issues – website may be slow or have temporary downtime; no time to troubleshoot
- Wrong information – no time to correct errors before departure
- Airport WiFi unreliable – uploading forms on airport networks is risky
TDAC at Airline Check-In
This is the most important aspect of TDAC timing that many travelers overlook: airlines are required to verify TDAC compliance before allowing boarding – similar to how they check visas.
At the departure check-in counter (in your home country or connecting airport), the airline agent may ask you to show your TDAC QR code. If you have not submitted TDAC yet, you may be required to:
- Complete the TDAC immediately on your phone at the check-in counter
- Wait for registration to process before receiving your boarding pass
- In extreme cases, be denied boarding
What If I Forgot to Complete TDAC?
If you realize you haven't submitted TDAC yet, here's what to do based on your situation:
You're still at home or hotel
Complete it immediately at tdac.immigration.go.th. Takes 2–5 minutes. Save the QR code screenshot and proceed.
You're at the airport, haven't checked in yet
Find a café or waiting area with reliable WiFi. Complete the TDAC before approaching the check-in counter. Show the QR code when checking in.
You're on the plane without TDAC
If your flight has WiFi (select international flights), complete the TDAC immediately. Otherwise, complete it upon landing using mobile data before approaching immigration. Be prepared for delays.
You've landed without TDAC
Enable mobile data and try to submit TDAC while still in the aircraft or in the airport terminal before reaching the immigration queue. Immigration officers may assist, but you may face delays.
TDAC Timing for Overnight Flights
For flights that depart late at night and arrive in Thailand early the next morning:
- Submit the TDAC the day before departure (when you're still at home)
- Your TDAC arrival date should be the day you land in Thailand
- Example: Depart Monday night at 11 PM, arrive Bangkok Tuesday 6 AM → TDAC arrival date = Tuesday
- Complete it Monday morning or afternoon – well before heading to the airport
TDAC and Connecting Flights
If you have a connecting flight through another country before reaching Thailand:
- One TDAC per person covers the entire journey to Thailand
- Enter your final arrival date in Thailand (not the date you depart your home country)
- Enter the flight number of the leg that arrives in Thailand
- Submit TDAC before the first leg of your journey
- Airlines on connecting routes may also check TDAC at check-in of the first flight
How Long Is TDAC Valid After Submission?
The TDAC is tied to a specific arrival date and flight. It remains valid from submission until your arrival date. There is no expiry period after submission – as long as you arrive on the date you specified, your TDAC is valid.
If your arrival date changes (flight delay, rescheduled travel): submit a new TDAC with the updated arrival date.
No. The system only accepts TDAC submissions within the 72-hour window before your arrival date. If you try earlier, you'll receive an error. Set a reminder to submit 72 hours before your flight.
Yes. You can submit multiple TDACs for the same passport/trip. If you submit one with an error, simply submit a new, correct one. Use the most recent QR code at check-in and immigration.
If your flight is delayed to the next day, submit a new TDAC with the correct arrival date. Minor delays (same-day arrival) are generally not a problem – the date can still match.
There is no explicit "penalty fee" for late submission. However, arriving without TDAC may result in: denied boarding, immigration delays, or in extreme cases, entry refusal. The safest approach is always to submit 24–48 hours in advance.