Shelly Beach is probably the best and most accessible spot for snorkeling in Sydney. Shelly beach is a small beach near Manly, it is protected from the ocean by a large reef on the right side of the beach when facing the ocean. This reef protects the Cabbage Tree Bay Aquatic Reserve against the waves and the currents. Both sides of shelly beach are suitable for snorkelling. It is a good place for beginners and more experienced snorkelers as there is a huge diversity of fishes to see. In Shelly beach it is likely that you will see Blue gropers, Crimsonband Wrasse, Australian Mado, Stripey, Hulafish, and if you are lucky you could even see some sea horses, carpet sharks, dolphins, sea turtles and pilot whales.
Compilation of snorkeling video at Shelly Beach:
Earth view of Shelly beach, you can see on both sides the large rocks that are ideal for swimming and snorkeling.
Shelly beach is a great place to snorkel if you live in Sydney, but don't take your car to go there as the parking is small and expensive. It is quite easy to go there by ferry or by bus.