What are the steps and requirements to apply for a 1-year extension of an OA retirement visa in Bangkok?

In Bangkok, you will go to the Chaeng Wattana immigration office.

Remember, you need to show proof of insurance from approved companies in Thailand to get an extension from Non-OA entry. You will be given an extension up to the earlier date of one-year or the validity of that insurance policy. Attached is general information for an extension based on retirement. You need to go to CW to get THIER latest handout.

1) I know a bank letter is needed but how should the letter be dated in order to fit the application ?

-> Bangkok accepts a bank letter within 7 days including the issued date

2) do I hv to leave my passport there and about how long can I get it back with a successful application ?

-> No, Bangkok wouldn't hold your passport. You will get your extension stamp inked in within the same day while you are waiting at the immigration office.

3) could I apply for the multiple entry visa at the same time as I apply for the retirement visa?

-> You can apply for a re-entry permit (not a visa) AFTER you get your extension inked into your passport, can do so on the same day. Multiple or Single re-entry(ies).

4) is there a form I have to fill in for the retirement visa? could I hv the link please ?

-> Bangkok has its own form with an additional field stamped. Better to get one at CW.