The Manly ferry from Circular Quay is one of the world's great public-transport rides — a 30-minute scheduled ferry crossing of the entire main basin of Sydney Harbour, threading between yachts and freighters, past the Opera House, Bridge, and the eastern naval and luxury suburbs (Rose Bay, Watsons Bay) before crossing the Heads (the harbour mouth) and docking at Manly Wharf. At 9.50 AUD with an Opal card, it's the cheapest harbour cruise in Sydney — and a daily commute for thousands of locals.
Departing from Wharf 3 at Circular Quay every 20-30 minutes, the ferry is a roomy double-ended cat with extensive open-deck seating front and rear. Sit on the upper deck on the right side outbound for the best photos: Opera House passes close on the right immediately after pulling out, Fort Denison mid-harbour, the eastern beaches and headlands beyond. The crossing through the Heads (where Pacific swell meets the harbour) can be choppy in southerlies — pleasant on a calm day, sometimes a proper rolling motion in strong wind.
Manly itself is the second-half attraction. The 100-metre Corso pedestrian street links the harbour wharf to the ocean Manly Beach in a 5-minute walk through a strip of bars, cafes, and surf shops. The 10 km Manly Scenic Walkway loops along the harbour-side cliffs to Spit Bridge with views all the way back to the city — the second-most popular Sydney walk after Bondi-Coogee. For shorter visits, walk the beach esplanade north 30 minutes to Shelly Beach for a quiet snorkel and seafood lunch.
Buy an Opal card at any 7-Eleven or convenience store and tap on/off — daily caps mean if you do other ferry/bus rides the same day, you stop being charged after 17.80 AUD. Last ferry from Manly back to Circular Quay departs around midnight on weekends, earlier on weekdays. Check ferry timing for sunset cruises specifically — late afternoon outbound (4-5 PM) followed by an evening at Manly and a sunset return is the classic schedule.