Sydney

Yes — and it's the single best cruise-day walk in Australia. From OPT it's roughly 700 meters along the Circular Quay foreshore to the Opera House forecourt, maybe 8–10 minutes at a relaxed pace. The Royal Botanic Garden gate is immediately past the Opera House. The Rocks historic district is directly behind OPT, also 5 minutes on foot. Most cruise passengers from OPT never need transport on shore day at all unless they're going to Bondi.

From OPT or central Sydney, the 333 bus from Circular Quay to Bondi Beach runs frequently and takes about 30–40 minutes depending on traffic. Tap on with a contactless credit card (Opal-compatible) — fare is around A$5 one way. From White Bay, you'd need to taxi into the CBD first, then catch the 333 — budget 60 minutes minimum each way. Bondi is a real beach with real waves; if you actually want to swim, factor in time for the rip-tide reality check before you commit to the day.

Tight, and we'd usually say no. Katoomba (the main Blue Mountains town for the Three Sisters and Scenic World) is about 90 minutes by train from Central Station each way, around A$30 round-trip with an Opal card on a Sunday cap. Add transit to Central from your terminal, plus the walk or shuttle from Katoomba station to the lookouts, and a 9-hour port day evaporates. If your ship is overnighting in Sydney, it's a great second-day plan. On a single port call, do the harbour and the city — the mountains will be there next time.

BridgeClimb Sydney runs guided climbs over the arch of the Harbour Bridge — about 3.5 hours door-to-door including the safety briefing and harness fit. Prices start around A$300 per person and go higher for dawn or twilight slots. The view is genuinely extraordinary. The catch on a cruise day is the time block: you cannot be late getting back to the ship, and BridgeClimb won't let you skip the briefing. Only book if your ship is in past 7pm or you're on the first morning climb.

Yes — Sydney rates as low-risk on the U.S. State Department's travel advisory (Level 1, the lowest tier), which is the same rating given to most of Western Europe. Petty theft happens around tourist density (Circular Quay, Darling Harbour) but violent crime against visitors is rare. The bigger cruise-day risks are the sun and the surf: UV in Sydney summer (December–February) is genuinely punishing, and Bondi rip currents drown people every year who think calm-looking water means safe. Hat, SPF 50+, and swim between the red-and-yellow flags only.

Card. Australia is effectively cashless for cruise-passenger purposes — contactless tap works on every bus, ferry, and train (no need to buy a separate Opal card; your contactless credit card is the Opal card), and cafes and restaurants almost universally accept tap. You don't need to change money on arrival. Note that some smaller venues add a card surcharge of 1–2% on transactions; it's legal and disclosed on the receipt. Carry maybe A$50 cash for tips and the occasional market stall and you're set.