Do saltwater crocodiles swimout to sea?

There are three related species - crocodile, alligator and ghariyal. Crocodiles have active lingual (on tongue) glands that can secrete salt - these glands are present also in alligators but aren't active. That's why crocodiles can live in the ocean where alligators can't survive for long (ghariyal is a purely freshwater species with no such gland at all).

Though the crocodiles are poor swimmers, the larget living reptile, called the estuarine crocodile (Crocodylus porosus) can ride sea waves and cross the sea to another nearby land area. They live in mangrove forests or estuaries near the seashore.