What should I do about my 90-day report if I leave Thailand just after my due date?

it is a common misunderstanding of the "window to report in person" for a 90 day report <- which is from 2 weeks before the due date until 1 week after the due date (a 3 week window)

As you already did one 90 day report in person you should now be in the system to file this report online (if you have a TM30 filed for where you stay)

you can apply online from 2 weeks before as well so just sent a reminder to apply online on Apr 13th and see if it gets approved or not

worst case it will be rejected

and then

you either go in person and file

OR do nothing and just stamp out of the country (there is no fine when you exit the country) 😮

Passport control doesn't care if you ever did a 90 day report or not, just take the 90 day report receipt you have out of your passport when you go to stamp out

Since you already filed in person you can try creating and account and file online anywhere from 14-7 days before your due date. If successful you'll get 2 emails, first says they received your report, 2nd is the confirmation that it's been accepted.

You can file a 90 day report in person from 2 weeks before the due date so just go and file one any time after April 13th before you leave and you'll be fine

The up to 7 days after is NOT a grace period where you can leave the country it's a window when you can file a report in person.

The rule works like this, in the country for 90 continuous days you file a 90 day report

The grace period is for making a report, not for leaving the country. Will you get fined if you miss this report, maybe if an eagle eyed IO spots it next time you visit the office