We’re a very beachy country. 
The best ones are further up north, either north of NSW or in QLD.
I loved Green Island when I went. Shallow, clear, cool (not cold) water that goes out so far. 
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If you ever end up down this way, that and Shark Bay in WA are nice places to visit. No sharks in the bay, just dolphins. 
(Or you all can help me win the lottery, and I’ll bring you all down myself. 
)
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Bondi Beach is about an hour’s drive from where I am. It’s a bit overrated compared to the less crowded places you can go elsewhere. It’s probably up there because the food is good, and it doesn’t require a trip outside of Sydney – you can have lunch in the city and be on the beach 20 minutes later.