I am currently in Thailand with a Non-B visa and also have a work permit. My non-B is only for 3 months, I know there has to be a minimum number of days left on the non-B to extend it to a year. Does anyone know what that minimum number of days is?

1, but you can do it as early as 30 days before the expiry date. One is advised to do it early and not to wait till the last day, in case you need extra documents etc.

1, but you can do it as early as 30 days before the expiry date. One is advised to do it early and not to wait till the last day, in case you need extra documents etc.

cheers Mario, but you can guess it dropped out of my head until now when I have 15 days left. I want to know if I can do it next Wednesday, or if thats too late.

You should be able to do it but only the office involved/officer can directly answer.