It is confirmed! Scooby-Doo does have a bellybutton!

I did not edit in his bellybutton (expect for the red circle to point it out). His bellybutton is in the actual show.

This is from the episode 'To Switch A Witch'. Very briefly for a few frames you can see Scooby-Doo's bellybutton. It looks to be an innie.

I just wish it was featured more often. But he is often walking on all four legs, so it would be very rare that we would see it.

Note: I took these pictures myself on my phone, so they are aren't too clear.

Scooby-Doo © Hanna-Barbara