We took the ferry from Circular Quay to Pyrmont Bay. It’s a fun, cheap way and you go under the bridge and pull up next To Luna Park on the journey there. Then we walked around Darling Harbor and crossed the pedestrian bridge and took the ferry back from Barangaroo. Another day we did the trip to Manly and back. Darling Harbor was $6 each way and the Manly round trip if you take the public not private ferry was about $16. Compare to a sightseeing cruise cost this was a really nice and inexpensive way to see pretty much the entire harbor are to the Pacific Ocean. It was very memorable.