Hello,

I have a NON 'O' visum, that shortly expired, i would like to obtain my first extention

When do i have to ask my extention based on marrige with a thai citizen, or based on pension,

before the end of the visum expired, or before the last visa run, so before the end 15 month?

Thanks in advanced

You can apply for an extension of stay during the last 30 days of your current 90 day entry. You could of extended any of the 90 day entries you got from your visa.