Published: 15 January 2026 | Last updated: 10 September 2026
Disclaimer: This article is published by an independent travel information portal and is not affiliated with the Royal Thai Government, the Immigration Bureau of Thailand, or any official agency. Always verify requirements at tdac.immigration.go.th before travel.
Flying from Heathrow to Bangkok requires completing the Thailand Digital Arrival Card (TDAC) within 72 hours of your arrival time in Thailand. This free digital form replaces the old TM6 paper card for 2026. Submit it before boarding to generate your mandatory QR code for the immigration checkpoint.
Complete the form via the THIM app or web, and save your QR code offline before takeoff – internet at Suvarnabhumi can be unreliable.
What Is the TDAC and What UK Travellers Need to Complete It
The Thailand Digital Arrival Card (TDAC) is the 100% free digital replacement for the suspended TM6 form, submitted at tdac.immigration.go.th to produce a QR code for Thai immigration.
Implemented in May 2025, the Thailand Digital Arrival Card requires all non-Thai nationals to register their entry details online. According to the Immigration Bureau of Thailand’s official announcement No. 123/2568 (May 2025): ‘All non-Thai nationals entering via international airports must present a TDAC QR code upon arrival. The submission window is 72 hours prior to the scheduled arrival time in Thailand.’ British citizens must still submit TDAC despite the 60-day visa exemption. Avoid third-party scams charging fees for this complimentary requirement.
Before beginning the application, gather the following details:
- A passport with a minimum validity of 6 months from your date of entry.
- Your specific flight number arriving in Bangkok.
- The exact postal code of your first Thai hotel or proof of accommodation.
- A valid UK mobile number (+44).
When to Complete the TDAC: The 72-Hour Rule for UK Travellers
Submit the Thailand Digital Arrival Card within 72 hours of your Bangkok arrival (ICT), not UK departure – the 11-hour BST to ICT shift means the deadline falls earlier in UK time, as shown in the table below.
Example: If your flight TG916 departs LHR on 20 June 2026 at 21:00 BST and arrives BKK on 21 June 2026 at 15:00 ICT, your 72-hour window opens on 18 June 2026 at 15:00 ICT (05:00 BST). You can submit any time between 05:00 BST on 18 June and 04:00 BST on 20 June (the morning of your departure).
| Flight Pattern | LHR Departure | BKK Arrival (Local) | Latest BST Submission |
|---|---|---|---|
| Direct (TG916) | 21:00 | 15:00 (+1 day) | 04:00 (Departure day) |
Flying via Dubai or Doha: Which Flight Number Do You Enter?
The TDAC demands accurate departure details for your final approach. If connecting on a single ticket, you must enter the final leg arriving in Thailand (e.g., QR836). Do not use your initial London flight number. This ensures Thai authorities process your entry correctly, distinguishing you from transit passengers who do not clear immigration.
How to Complete the TDAC: Step by Step
Submit at tdac.immigration.go.th with passport data, flight number, hotel postal code, and health declaration to get your QR code.
Personal Information
Enter exact passport details.
Journey Details
Input the flight number of your final leg arriving in Bangkok.
Proof of accommodation
Provide your first hotel address, mandatorily including the postal code.
Health declaration
List all countries visited within 14 days prior to arrival.
TDAC for Children and Infants – UK Family Travellers
The TDAC system allows UK families to streamline entry by submitting a group application for up to 10 travellers. Whether completing this via the web portal or the THIM app, always save the final QR code offline before your Heathrow departure.
Can You Change Your TDAC After Submission?
If your flight is delayed, edit travel dates, flight numbers or accommodation within the existing Thailand Digital Arrival Card – no new form needed unless passport details change. Non-editable fields (passport name, nationality, DOB, passport number) cannot be altered; mistakes mean your process must start over.
London Heathrow to Bangkok: Routes, Timings, and Your TDAC Pre-Flight Workflow
Submit TDAC before flying and save the QR code offline – Heathrow airlines don’t check it at boarding, but Thai immigration does on arrival.
When I submitted my Thailand Digital Arrival Card from home 48 hours before my TG916 departure, I saved the QR code as a screenshot. At Heathrow Terminal 2, the gate agent did not ask to see it, but upon arrival at Suvarnabhumi, the immigration officer scanned it in under 10 seconds. This saved me at least 20 minutes compared to passengers filling out paper forms at the counter.
Although Border Pass holders are exempt, standard UK travellers on Thai Airways flights TG916 and TG917 should follow these steps:
2 days before departure
Complete the TDAC online from home.
At Heathrow
Use Terminal 2 Wi-Fi to submit the form if you missed the earlier window.
On the plane
Download your confirmation code for offline use before losing network coverage.
At Suvarnabhumi
Present the saved digital document directly at the Thai immigration checkpoint.
TDAC Thailand Heathrow FAQ
Do I need to complete the TDAC before leaving the UK or on arrival?
Submit TDAC up to 72 hours before Bangkok arrival or on arrival; completing it before leaving the UK speeds up entry.
Does the 72-hour deadline count from UK departure or Bangkok arrival time?
The 72-hour window counts strictly from your scheduled arrival time in Bangkok (ICT). Due to the 11-hour time shift, calculate this deadline based on landing time, not UK departure.
Can I complete the TDAC at Heathrow before boarding my flight?
Yes, using Wi-Fi at Heathrow Terminal 2. While UK airlines don’t systematically verify it at the gate, Thai immigration requires the QR code upon arrival. Download it offline before takeoff.
Do I have to pay for the Thailand Digital Arrival Card?
No, the Thailand Digital Arrival Card is 100% free at tdac.immigration.go.th. Beware of third-party scams charging fees.
What if my Heathrow flight is delayed after I submit the TDAC?
If your flight is delayed, edit travel dates, flight numbers or accommodation within the existing TDAC – no new form needed unless passport details change.
Do I need 20,000 THB cash for the UK visa exemption?
Yes, British citizens entering under the 60-day visa exemption may need to show 20,000 THB cash per person. This is separate from the TDAC requirement.
Which flight number do I use if connecting through Dubai or Doha?
On a single ticket connecting through a Middle Eastern hub, enter the flight number of the final leg landing in Thailand, not your London departure flight.
Can I edit my TDAC if I make a mistake with my passport details?
No, core identity fields (passport name, nationality, DOB, passport number) are non-editable. If incorrect, you must submit a new Thailand Digital Arrival Card.
About the Author: This guide was written by Alex, a UK-based travel writer who has flown from Heathrow to Suvarnabhumi three times in 2025-2026 and personally tested the TDAC submission process on both TG916 and connecting flights via Doha.
