Crocodylus porosus turns up on remote islands hundreds of kilometres from any breeding population, which poses an awkward problem. A reptile that swims at a modest sustained pace should not be able to make such crossings under its own power.
Acoustic and satellite tagging of adults along the Cape York coast offered an answer. Tracked animals timed their departures to match the tidal flow, travelled while the current ran with them, and rested on the riverbed or bank when it reversed. One tagged male covered several hundred kilometres of coastline over about a month using this pattern. The mechanism is conserved energy rather than endurance.
What the tracking does not show is deliberate navigation. Whether the animals select a destination or simply exploit whatever current is available remains unresolved, and the published sample sizes are small. The idea that crocodiles are powerful long-distance swimmers is the part most often reported incorrectly.