Yes, most likely, you cannot apply for a long-term in-country visa and/or yearly extension at the local immigration office inside Thailand until you cancel your existing extension, regardless of whether it's expired or not.

Go to the immigration office that issued that extension to cancel it next time you are in Thailand. You may also need to cancel your old work permit if it's not cancelled as well. You may or may not be fined (same rate as overstay fine, up to 20K baht) for not cancelling it properly, depending on when your extension based on employment expires.

@Tony *******

, you can apply for an initial in-country Non-O visa within the 60 days on visa exempt entry no problem if you meet the requirements.

@Nicholas ******

, because the British embassy in Thailand wouldn't issue an income affidavit. You are in a different situation from the OP's. Please check Tod's comment.

@Robert ********

, That totally depends on the country that issues the passport. Some countries void/invalidate the old passport at the time of issuing a new passport. Some do at the time of the new passport application.

You use a new passport to both leave Finland and enter Thailand.

Make sure you show the old passport together when you enter Thailand, and be sure you are stamped in a new passport based on the re-entry permit in your old passport.

Once you are back in Thailand, bring both passports to the immigration office that issued your extensions to apply for the transfer of stamps to the new passport.

@Stephan **********

, as I wrote, some offices are not happy with pdf ver even if it stamps by bank. They want a bank printed transaction history. Better to check in advance.

@Stephan **********

, not all immigration offices accept the PDF version sent by email. Some allow only bank printout versions, and some accept PDF if it's with an actual bank stamp. You better check with your local office what versions they'd accept for financial proof.

@John ***

, It depends on the office. If your local office is CW, bank letter and transaction history can be up to 7 days old, along with the bank book updated on the day of application.

You (every foreigner, regardless of what type of visa/entry) need to submit TDAC, the application window is from three days before until you enter (are stamped in at passport control at your entry point to Thailand).

So, you are going to apply for an initial in-country Non-O visa based on marriage to a Thai male. You can apply for it anytime now, as long as you still have days (depending on your local office) remaining with your current stamp.

You don't have to wait for a specific time.