A passport that is valid on your departure date is not always a passport that is accepted at your destination. The requirement is set by the countries you visit, not by the trip you booked, so the useful move is to check each one while there is still room to act.
The rule belongs to the country, not to the cruise
Each country sets its own entry requirement, and a single sailing can touch several of them.
You will see a six-month rule quoted everywhere. It is a real category of requirement — some countries want a passport valid for a defined period beyond your arrival or your departure — but the exact period, and whether it is counted from entry or from exit, varies by country and can be updated. Read the current requirement for every country on the itinerary, including any where you only change planes.
The U.S. State Department publishes a country information page for each destination, and each destination's own consulate publishes the requirement it enforces. Those two sources beat a forum thread, and they beat this guide.
Count backwards from the dates, not forwards from today
Compare the expiration date on every passport with your return date, and write down the gap in days.
- Everyone traveling, including infants and any adult joining later
- The return date, not the departure date
- Every country the group enters, transits or docks in
Renewals take as long as they take
Processing times are published and they move through the year, so read the current figure instead of remembering the last one.
A child's passport and an adult's are not always issued on the same terms, and a minor's application can carry extra requirements, including both parents. If a renewal is needed, starting it before you finish choosing dates is the cheapest version of that decision.
The name on the passport is the name on the booking
A booking made with a nickname, a maiden name or a missing second surname is a document problem that surfaces at the counter.
Compare the booking against the document, letter by letter, the week you book. A correction asked for early is a message. The same correction asked for late is a supplier procedure with its own terms and timing. Ask today what a correction involves on your booking — asking costs nothing.
Passport dates and names are the part of a trip nobody can solve on the morning of departure. Check them in week one, while every fix is still small.
Details that change by date, supplier or destination should always be confirmed before you decide.