[harry8]

Swimming in Sydney Harbour is also possible. They did it for a leg of the triathalon in the olympics a couple of decades back. Wouldn't recommend though, there's a lot of bull sharks in there and they're kinda aggressive. Netted beaches and bays are the go.

[lmpdev]

Only ~1,000km north, bullsharks have been filmed swimming in groups of ~150 near the Story Bridge in the Brisbane River

To any tourists visiting Aus, please only ever swim where locals swim and only between the flags if on the coast

[mcv]

I live in the eastern docklands of Amsterdam, and there's always lots of swimming here. Amsterdam has invested a lot in cleaning up its canals and other waterways and water quality has improved a lot over the past couple of decades. And there's no sharks.

[dredmorbius]

Or the North Sydney pool, when it re-opens, with luck next month.

Not open water, but salt, and an absolutely gorgeous location.