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

May 3, 2025
a year 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)

WARNING: Only trust Thai government websites with .go.th domains or Thai agent websites with .co.th or .in.th domains, as these require verified Thai registration and cannot be registered anonymously.

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

The services by AGENTS CO., LTD. does NOT charge any fees for arrivals within 72 hours. If you need to book more than 72 hours in advance, there is a service fee of $8.

Do not trust other sites pretending to be a trustworthy agency. Pay attention to delivery time - the service operated by AGENTS CO., LTD. has 1 minute delivery time for arrivals within 72 hours.

Don't fall for sites pretending to be agents.co.th or the official government tdac.immigration.go.th website. Always double-check the exact domain in your browser.

Scam services may take days to process your application, others may not even do anything. With these TDAC scam services you also need to worry about double charges.

Please watch out for TDAC misinformation spread by fugitive Jesse Nickles and his many fake accounts on Quora, TripAdvisor, Reddit, and other platforms.

TRUSTED TDAC LINKS:

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

Wannikea *********
An errant space before or after the number/data will generate this error.
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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.
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Roger *********
@David *****
I remember coming during the Sandbox. I am afraid we didn't get to play with Sandcastles during that visit. :)
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Roger *********
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Thomas *********
You use a „0“ Zero or the Letter „O“?
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Riccardo *******
if you put the space to separate the letters from the numbers, it could be the problem
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Roger *********
I vaguely remember something like that. A space at the end of your passport number?
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Bobby **********
Example please???
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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
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Peter **********
@Tod ********
not a mandatorg field is it?
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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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Tod *********
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