> to extend 45 day VOA (American)?
You do not have a visa on arrival, you have a 45 day visa exempt.
>correct Immigration Office / location in Bangkok
You would go to Muang Thong Thani immigration office.
The GPS location is at
13.
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78,100.
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33
>And is an online appointment required
Yes. You would choose Counter K
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You will need to bring the following with you:
Different immigration offices have different requirements, but all require the following:
1. Your passport and:
a. a copy of your data ("picture") page
b. a copy of your most recent visa (if you have one)
c. a copy of your most recent stamp
d. a copy of your departure card
2. [MAYBE] A TM30, filed in the immigration office.
3. The Extension of Stay forms. For Bangkok immigration, you can find it in the FILES section of this group.
4. 1 passport pictures
5. 1,900 THB.