Can I change my work visa to a marriage visa in Thailand if my wife is Thai?

@Poh ************

you will NOT be changing ANY visa, (because you don't have a visa now) you are on an extension of stay based on employment AND all you'll be doing is changing to an extension of stay based on marriage. In essence you're just changing the reason for your extension,

Cancel your current extension based on employment, meet the requirements for the extension based on marriage and apply for it as soon as your current extension is cancelled. ,

>is it possible to change my work visa

I'm almost 100% certain that you do not have a "work visa", but instead a large stamp in your passport called an "extension of stay based on employment". If you do, you can change the reason for your stay from employment to supporting a Thai wife - if you are legally married with the rose border certificate. This will require either a salary of 40K THB a month, OR 400K THB in a Thai bank account in your name for 2 months.

Getting this extension of stay based on marriage will also require other documents and forms, that may be specific to your immigration office. As James said above, contact your local immigration office for the handout.

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Extension Married Thai National

I placed on your post.

Take your Thai wife with you to Thai Immigration and ask for their requirements to obtain a one year extension based on marriage to Thai..