I have a 90 day non-imm type O visa and I plan to apply to extend it for a further 12 months.

I have been told I can apply when the current visa has 30 days to run.

So, can I check if anyone knows, does this application have to be made when the visa has exactly 30 days to run, or is there any flexibility - is it 'within 30 days' for example.

Thanks for any advice!

anytine within 30 days is fine

Anytime during last 30 days.

Your extension will start when your current permission to stay ends, so you can do it early.

Just make sure that you meet the financial requirements when you apply. If for retirement extension either 800k in a Thai bank in your name only seasoned for two months, proof of at least 65k/month from overseas (Embassy letter) or a combination of both. If for a marriage extension the 800k goes down to 400k and the 65k goes down to 40k *money does not have to be from overseas) and no combo is allowed.