I know a couple of people who have seen them in the water while diving (for barramundi) in areas they thought were too far south for crocs. And there's some crazy divers who dive in Darwin harbour which to me seems insane, but they've been doing it for 30 years.
But typically no you wouldn't knowingly get in the water with them. You do hear of tourists getting taken from time to time.
Dang. I googled it and you're right. They swim in Darwin Harbor. They have triathlons and competitions and stuff.
Gators and Crocs freak me out on some lizard brain level. I could never get in the water knowing there's even the possibility.
Watching this video of a croc along side a fishing boat gives me chills.
Do Aussies frequently swim with Saltwater Crocs?