Time Out says
Congwong Beach is located within the Botany Bay National Park and is in the care of the National Parks and Wildlife Service. It is not a surf beach as it faces Botany Bay rather than the open ocean. It's about 14km from the city, but well worth the drive (or a ride on the express L94 from Circular Quay) – once you're out here, you'll feel like you've headed much further down the coast. There's a good mix of everything: families with kids; couples; seniors; singles and pretty much every other type you can imagine soaking up the sun. Congwong gets bonus points for the Streets ice cream boat that arrives on weekends peddling treats.
Want more? Check out our guide to Sydney's best beaches.