When can I access the 400,000 baht after my marriage visa extension is approved?

Okay, there are ONLY two ways it works;

At SOME immigration offices ; you bank the 400K baht in a thai bank account in your name only for 2 months before you apply for your yearly extension, you get a 30 day under consideration stamp AND when you go in on that date you update your bank book to show them the 400K baht is still there. <- once you get the year extension inked in you can use the money

AND

At OTHER immigration offices; you bank the 400K baht in a thai bank account in your name only for 2 months before you apply for your yearly extension, you get a 30 day under consideration stamp AND when you go in on that date you DON'T update your bank book and show them the 400K bhat is still there <- once you get the 30 day under consideration stamp inked in you can use the money..

It's one or the other :P BUT seeing as you said you already got your year extension inked in you're totally free to use the money..

Bear in mind that to get your next years extension you’d need to have it back up to 400k two months prior to applying.

One of the enduring problems with “definitive advice” in this forum is that definitive advice for BKK or Ubon immigration won’t be definitive advice for your local immigration. So while it sounds like someone is being a smart ass to say “ask immigration” it’s actually the best advice available.

Unless, of course, someone has recently renewed their visa in your specific office.

Once you have your years stamp you can spend it down to zero. If you are on a “under consideration” stamp many offices will want you to keep it in your account until you get the full year stamp.

Ask immigration you were only there a couple of weeks ago

Best to leave it in untill they stamp the years extention in your passport. Then you're good to go. If you got it already then you can access your funds.