If you are bored of following a line in a normal swimming pool, just try one of the rockpool in Sydney! And swim in salt water with fishes!
Sydney's ocean pools are a great way to cool down and avoid getting sand all over you. A lot of Sydney's beaches have ocean pools that take the ocean water into them and cycle it in and out so the water in them is always fresh and clean.
Ocean pools are are also a great way to take the kids to the beach and not worry about them getting buffeted around by the waves.
Sydney's ocean pools are open all year round but as these beach pools are fed straight from the ocean there's no heating or anything so you need to be brave to do this one in winter!