Do I need to do my 90 day report ? I'm flying out on 5 June ,,and 90 day report is due on 31 may?

Do it online very quick process.

 

You can leave without doing it. 

IIRC the grace period for a 90 day report is seven days. You should be OK, although as the second post said, easy to do online.

@mellAre you returning in the near future? You can do it 14 days prior to your due date by using the online system here:

 

Apply for Notification of Staying in the Kingdom

 

or you can do it up to 7 days after the due date, but at that point you must do it in person.

 

You can also do it by post.

Why should I do it if I don't need to please read my post I'm on extension of stay yearly, I leave 5 days after my 90 days is due, do I need to do it or I just go to the airport and depart,?

34 minutes ago, mell said:

Why should I do it if I don't need to please read my post I'm on extension of stay yearly, I leave 5 days after my 90 days is due, do I need to do it or I just go to the airport and depart,?

It is best that you do it before departing. 

Because when you return on the Re-Entry Permit of your current 1-year extension of stay, and you go to Immigration for your next 1-year extension, they might notice that you did not do that 90-day report before departing.  And that will result in a fine (typically 2.000,- THB). 

There are no other consequences besides that potential fine of not doing it, so you might consider skipping it when it is currently inconvenient for you to do it.