Can I change my Non-O multi-entry visa to an extension of stay anytime before it expires?

@Steven ***************

You use the TM7 application for extension of stay form. It's two sided, print it on one paper front to back.

You should swing by the immigration office BEFORE you are going to apply for your extension and get the hand out that lists the requirements to get a yearly extension based on marriage because they are far different from the requirements to get a visa from a thai consulate in another country

You're confusing two separate things.

The Non-O VISA <- that you got in a thai consulate in another country is NOT the thing that lets you stay IN thailand. :O It let's you ask to be let in. It's the rectangular stamp you got when you entered the country (in your case a 90 day stamp) that lets you be able to stay IN the country.

As people pointed out in Bangkok, you can apply for an extension when you have 45 days or less left on your current entry stamp from your Non-O visa (the visa expiration date has nothing at all to do with it).

Earliest is 45 days before your existing admitted to stay stamp expires, some Imm Offices are 30 days

You can apply for extension starting 45 days before the date you are allowed to stay until (that's the date indicated on your last entry stamp)

I had non 0 Visa too, i extended 2 times before my visa expired. As I remember around more 30 days early is okie. Because in case, last time I had problems, then i had enough time to prepare again.

My marriage visa was sorted out with no problems, from start to finish, and attended the wedding to ensure everything was correct.

I’m going to apply for a retirement visa, in my opinion employ a reputable Thai firm based in Thailand who specialises in this field of work.