How long before a visa expires can I extend it in Thailand?

@Tod ********

thanks, will go try that by the end august

@Pascal *******

you should be able to do it when you have 30 days or less on your current extension BUT if they give you grief you could show them proof you're going to be leaving the country and not back before the extension expires.

@Tod ********

my ext of stay for a non o based on marriage expires on 7 October, I will be out of the country probably, is it in every immigration office possible to extend more early ? I know from past when i went to kanchanaburi immigration, one week before exp date, they send me home

In Bangkok you can apply for an extension of stay when you have 45 days or less left on your current stamp. They add the new year extension on to the expiration date of the current one.

Normally 30 days. Sorry.

You can only apply at the same Immigration Office as before.