Can I switch my Non-O extension from retirement to marriage when applying for my next extension?

Change to based on marriage no issue as has been posted already.

Note that your 12 month extension will start from when you apply as you are changing the reason what the extension is based on.

No big deal however if existing renewal date is preferred then apply late..

Not eg 45 days prior.

The answer is yes but I can only speak from my experience in my province of Nakhon Ratchasima. I was in the same situation last month. I arrived October 2024 and received a 90 day Non-O based on retirement and a one year extension of stay stamp all through an agent in Bangkok using their funds. From the moment I received my bank account (Krungthai) I faithfully deposited a minimum of ฿70,000 via Wise on the first of every month. All year long I read post after post about the problems of being on the “agency hamster wheel“ and was concerned about my extension renewal, especially being from the US and not being able to get an embassy certification for my retirement pensions. In July, my fiancé and I were married, and I soon decided to pursue switching the extension stay from retirement to marriage.

End result… just received my final extension and reentry stamps on Christmas Eve. Everything went even smoother than I hoped. The first trip to receive my 30 day “under consideration” stamp only took a half day at immigration including the very easy process of getting my statements and bank letter that morning at Krungthai bank. Also the home visit which they did that same week went very smoothly and actually was an enjoyable experience. Going back this week on the 24th for my final stamp was only slightly delayed because of the amount of people at immigration.

My suggestion to anyone (marriage or retirement) is to make sure you follow the list of items needed which you receive from your immigration office “to the letter” and more is always better than not enough when it comes to the supporting documents. I provided monthly statements from my US bank showing my military retirement and Social Security deposits as well as the monthly transfers via Wise. I highlighted each deposit and transfer (color coded by type) to make it very easy for them to see. I think this was helpful and appreciated by the IO officer. I also provided the online statements of benefits from both the military and Social Security accounting offices. They never asked for any certification from my embassy.

Again, I say this knowing that every provincial immigration office is different but want you to know what you asked is possible because I just did it in Nakhon Ratchasima. Best of luck to you and feel free to DM me if you have any questions.

When your current extension of stay is due for renewal you can switch to marriage assuming you meet the criteria. If you are currently using the 800k baht method it should be no problem as you have to meet the criteria for your current extension anyway which means you will have the 400k baht for the marriage extension anyway. But if you are using monthly transfers you need to be aware that not all immigration offices allow this for an extension based on marriage.

As long as you are currently on an extension based on retirement, there's no problem with applying for the next extension based on marriage instead. You just need to make sure that you meet the requirements for the new extension.

The people that have an issue are the ones that enter on or purchase a 90-day non-O visa based on retirement, and then decide they want to do the extension based on marriage instead (or vice-versa). They cannot do that because the first extension from a visa must be based on the same reason the visa was issued.