While there are the obvious pleasure of surf beaches, many visitors miss what is one of the great contemplative treasures of the Australian east coast, the rocky beach headlands with their natural intertidal rock pools. The rock pool is a world in microcosm, a glinting and glorious brilliant home to to dozens of small animals such as anemones, periwinkles, barnacles, crabs as well a intricate algae species, and sometimes, as you can see here emerald green sea grass. Rock pools are best viewed around somewhere half way between high and low tide. (Check the Tide Time Table at http://www.maritime.nsw.gov.au/docs/Tide_Tables.pdf).
One of the easy places to see rock pools is the northern rock platform at Balmoral Beach . To get there take the Taronga Zoo Ferry from Circular Quay ( this takes about 20 minutes), if you're up a for walk along the foreshore of Sydney National Park, talk the path to the right as you leave Taronga Ferry Wharf , heading north-east and you'll find the path which is well signed. Keep going around Bradley's Head, around Clifton Gardens Park, through Chowder Bay, where you can stop at either the Baccino kiosk right at the water's edge for a coffee or cold drink, or at the Baccino Cafe which is up the stairs a little further. If you don't feel like walking take the 238 bus from the ferry bus stop and get off at Balmoral Beach, just at the end of Raglan Street is probably the best spot.
You can take the Chowder Bay Road, which make a longish loop past the Sydney Institute of Marine Science, up the hill turning left into Middle Head Road, till you ge to the stairs down to Balmoral Oval. There is also a path just to the left of Baccino Cafe with stairs that go up and over the hill to the meet up with the Balmoral stairs. Down the stairs, take the path around the oval to Balmoral Esplanade. You can find a detailed map of this walk and other maps of Mosman at http://www.mosman.nsw.gov.au/mosman/place/maps.
If the weather is warm the beach is a peaceful place to swim, and on weekdays is not at all crowded. There are quite a few casual cafes with great coffee, like the Boatshed Cafe, if you're need lunch. Walk north along the beach, past the bus shed (remember this for the return trip!), past the small island connected by a curved bridge, past Bathers Pavilion (also a great place for lunch and the menu is posted near the front door ) and then along the beach, past the man-made 'babies pool) till you get to the rocks.
Some kind of light sandshoe is best for walking on the rock platform. This rock platform goes all the way around to Chinaman's Beach but this is quite a challenging work and you will find many wonderful rock pools just past the point. Don't take anything, shells or seaweed from the pools, as this is prohibited, some creatures, such as the Blue-Ringed Octopus are poisonous, so as general rule don't pick up sea creatures.
Once you've had enough in your rock pool viewing you can catch the bus back to the city from the bus shed. For an interesting and free bus ride around the district, you can do a circuit on the free Mosman Rider bus which runs every half an hour, there are bus stops for just next to Awaba Cafe on the corner of Awaba Street and the Esplanade. You can find information on all the ferry, bus and the free Mosman bus at http://www.mosman.nsw.gov.au/mosman/transport/public-transport.