I am cruising on Saturday and checked the Princess site for any updates. As of August 24th RAT tests for fully vaccinated and up to date cruisers is now 2 days.
PCR is within 72 hours.
Had my negative test results today almost booked for yesterday glad I didn't.
the 2-day window does not depend on the time of day the test was taken or the time that you board
for example, if your ship is scheduled to leave on Friday, you could provide proof of a negative result from an antigen test taken any time on Wednesday, Thursday, or on Friday
it must be administered or observed by a pharmacy, laboratory, healthcare entity or telehealth online service