I agree that Seaworld is the best for Toddlers, although if you do go to Dreamworld and its a warm day, get a world pass so you can go between Whitewater World and Dreamworld - DS LOVED Wiggles Bay in Whitewater World, its great. I found Dreamworld to be a bit 'tired' whereas we could have filled a few days at Seaworld

And the Duck Bus (Cant remember what its called but its a bus that can go on land or sea), DS LOVED that too!!