Actually, there are only a few areas you cant anchor
. Near Garden island (navy base), Circular Quay (ferry terminal), Darling Harbour and near commercial shipping
docks etc. . In summer Nor-easters you will find great anchorages near Taronga Zoo for a great view of the city, opera house, bridge etc.
Peaceful quieter anchorages will be found up Lane Cove river.
On peak occasions (NYE and Aus Day) there will be exclusion zones in place. But mainly that is for traffic rather than anchoring, due to the fireworks barges.
Once you have had enough of the harbour, head
up to the Hawksbury River (15-ish Nm nth) . Its a much nicer area surrounded by national park. There is plenty of public transport linking back to the CBD as desired. Some bays on the Hawksbury also have free moorings
When you get here, the "most" important thing is to declare, declare, declare. If you have any fresh meats, fruits etc "Border Force" will want to destroy it. So make sure you are really open with them to prevent a fine. They are ok with most tinned and packaged foods. But make sure they have access to all of it. We are one of the few continents without Foot and Mouth, Rabies and lots of other diseases that can affect our unique flora and fauna, so our authorities are anal about what comes in.
The upside of this is they may want to destroy any rubbish you have on board :-D
The same goes for any untreated wood you may pick up on some beach at some other country on the way. The general rule
of thumb is Varnished wood is usually ok. Raw woods, cane, straw etc isnt. But as long as you declare it, there is no fine. They will just let you know if it needs to be destroyed or whether to put it back in the locker.
Best Anchorages | Maritimo Sydney