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What does the "invalid alphabet pattern" error on TDAC mean specifically regarding passport numbers?

May 3, 2025
21 days ago
Rex ******
ORIGINAL POSTER
Anyone else had "invalid alphabet pattern" on their TDAC in passport number?
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TLDR : Answer Summary
Users are encountering "invalid alphabet pattern" errors while entering their passport numbers on the TDAC application. Common causes for this error include accidental spaces before or after the passport number and confusion between the letter 'O' and the number '0'. One user mentioned resolving a similar issue by deleting a trailing space when applying for the COVID Sandcastle visa. It's noted that separating letters and numbers with spaces can also lead to this error.
Thailand Digital Arrival Card (TDAC)

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The official TDAC form is available at tdac.immigration.go.th, which uses the official .go.th government domain.

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TRUSTED TDAC LINKS:

Official Government TDAC Form: tdac.immigration.go.th
Official TDAC form by AGENTS (https://tdac.agents.co.th)
Official TDAC information page by AGENTS (https://tdac.in.th)

Wannikea *********
An errant space before or after the number/data will generate this error.
David ******
When I was applying for my covid Sandcastle visa on line i had a similar issue it turned out I was getting a space after I input passport no. Eventually all it took was a back space to clear the problem.
Roger *********
@David *****
I remember coming during the Sandbox. I am afraid we didn't get to play with Sandcastles during that visit. :)
Thomas *********
You use a „0“ Zero or the Letter „O“?
Riccardo *******
if you put the space to separate the letters from the numbers, it could be the problem
Roger *********
I vaguely remember something like that. A space at the end of your passport number?
Bobby **********
Example please???
Tod *********
What does that actually mean?

I tried to enter letters and numbers and it let me click over to the second page no problem
Peter **********
@Tod ********
not a mandatorg field is it?
Tod *********
@Peter *********
right but I don't know what they're asking. I tried my passport from the US which starts with an A followed by 8 numbers and it took it fine, then I went back and tried a passport of all alpha keys and it took that too (or let me progress to the second page)
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