Do I need to file a 90-day report if I'm flying out after the due date?

@Eti****

even if you don't do this 90 day report you wouldn't be fined at the airport because the people that stamp you in/out of the country don't care if you ever filed a 90 day report or not.

It wouldn't be until you come back into the country, and go to do the NEXT 90 day report that they would see you should have done a 90 day report before you left and they could fine you the 2000baht before they'd let you do another report.

Now there's a good chance that if you didn't file this one when you came back and went to do the next 90 day report they wouldn't notice.

It's a crap shoot, I'd say IF you can go do your 90 day report before you leave go do it, if you can't, well deal with it when you get back and go for the next one..

there is no 7 day grace period. You are confusing the window of when you can apply in person (from 15 days before down to 7 days after the due date) with a grace period where if you leave the country during that 7 days after you don't file.

It doesn't work like that, if you're going to be IN the country when the 90 day report is due you need to file one