SYDNEY HARBOUR Various locations; 6.30am-9.30pm, free, australiaday.com.au The harbour will be abuzz, with the annual Ferrython race, a 21-gun salute received by the Navy's largest-ever flagship, HMAS Adelaide, and an RAAF flyover. The Enormous Horns and Junkyard Beats will perform on a custom-built floating barge, with a squadron of Russian Roolettes and the Red Berets' parachute display by the Australia Army in the skies above. There will also be an Australia Day Harbour Parade with decorated boats vying for the best dressed vessel prize, a tall-ships race and a fireworks display from a barge between two P&O cruise ships. 
OLYMPIC PARK Cathy Freeman Park, Sydney Olympic Park; 2pm-9pm, free, auburn.nsw.gov.au Sheep shearing and whip cracking demonstrations, children's entertainment, animal farm, pony rides, roving entertainers, indigenous workshops, amusement rides, mini train rides, food, arts and craft stalls and fireworks.
PARRAMATTA Parramatta Park, Pitt St, Parramatta; 6am-9pm, free, ausdayparramatta.com.au The day begins with a hot air balloon display followed by the CARnivale expo with more than 400 vehicles on display, including fire engines, trucks and military vehicles. There will also be performances from X-Factor finalists Jess + Matt, soul singer Nathaniel, country music legend Troy Cassar-Daley and pop artist Christine Anu, with Nickelodeon stars Dora the Explorer and SpongeBob SquarePants at the Kids Crescent throughout the day as well as a barbecue cook off, rides and a fireworks finale.
THE ROCKS The Rocks Chilled Summer Festival, various locations in the Rocks; 12.30pm-6.30pm, free, therocks.com Sydney's historic district has an all-day music program featuring some of Australia's hottest new bands, markets, croquet and an instant photo booth. Performers include alt-pop legend Katy Steele of Little Birdy fame, the Melbourne Ska Orchestra and Torres Strait Island rapper Mau Power.
WATSONS BAY Every Man And His Dog Stand-Up Paddling Event, Marine Pde, Watsons Bay; 8am-11.30am, everymanandhisdog.com.auEvery man and his dog are heading to Watsons Bay for a stand-up paddling race with pooches. There will be several other stand-up paddling races including a kids' race, a technical sprint, a dash for cash and 6km-long distance race. Registrations open at 7am, with great prizes on offer.