Mary River Wetlands Cruise from Darwin. Get an up-close encounter with Australia’s amazing wildlife on this Mary River wetlands cruise departing from Darwin. After traveling through the Outback town of Humpty Doo, climb aboard a high-powered speedboat for a 1.5-hour cruise through biodiverse waterways. Soak up the lush scenery as your expert guide points out native birdlife such as kingfishers, herons and kites. Keep an eye out for saltwater crocodiles lounging in the sun — the Mary River wetlands is the best place in Australia to spot the crocs in their native habitat! Book and Save 10%! Mary River Wetlands Cruise from Darwin.