When is my 90-day reporting due after an ED visa extension in Thailand?

okay, the way it works for "real schools" is; they usually don't give 90 day extensions on ED visas instead they give 60 day extensions. AND your 90 day report is due 89 days from the date you got your FIRST extension (even if that extension isn't for 90 days and it's not time to do your report until you get the second extension) ;)

So

@John *********

is correct (y), you wouldn't do a 90 day report on this extension, BUT once you get your next extension you will need to do the 90 day report on the 2nd of December .

Not sure why you would need to do a 90 report as your permitted to stay date comes before 90 days are reached

Seeing as you're on an ED visa you could always just go ask your school โรงเรียนสอนภาษาชำนาญจันทร์ ;)

i guess you have an ED visa, is this your fist EXtension of Stay on this visa

Didn't they put a paper in your passport when you got your extension that looked like this?

your 90 day report should be due 90 days AFTER that 4th Sept date (the date you got your first extension)

They usually put a paper in your passport stating when you get your extension stating when your first 90 day report is due.