We are taking a New Zealand/ Australis cruise. I found out that US citizens do not need a visa for New Zealand, gut Australis i'm not sure. Our cruise arrives in Sydney at 6:30am and we fly out at 3:00pm. We plan on going straight to Sydney's international airport for the cruise port. On the Australian customer website said if under 8 hours no visa is needed, but then it also said if in county less then 72 hours you do need on. Does anyone know?
A quick googling shows this:
If you are transiting through Australia, remain airside for a maximum of 8 hours /../ you do not need to apply for any advance visa.
This seems to only be valid for transit between flights, not when you arrive by cruise ship(?) I'm also not sure when you'll "stamp into" Australia, if that will happen when your cruise arrives or earlier? Will you spend time in Australia before the last day? Also, 6.30am-3pm is 8.5 hours, which is more than 8. Without more information, I would get a visa, which is only $20 and easily obtained online. If you're in doubt, perhaps ask the cruise line?