Passport validity rules travelers often miss

Most travelers assume a passport is valid until the date printed inside it. Many destinations disagree. The single most common reason people are turned away at check-in is a passport that is technically unexpired but does not meet the destination's validity window.

The six-month rule

A large number of countries require your passport to remain valid for at least six months beyond your date of entry — sometimes beyond your date of exit. Others use a three-month rule, and a handful only require validity for the duration of the stay.

Count from the day you land, not the day you book. If your passport expires within nine months of a trip, renewing early is cheaper than rebooking.

Blank pages and damage

Some border authorities require one to two completely blank visa pages. Amendment or endorsement pages usually do not count.

Water damage, a detached cover or a torn laminate can invalidate a passport at the discretion of the border officer, even if every page is readable.

Before you book

Check your government's official travel advisory page for the destination, and check the destination's own immigration authority. Airline check-in systems apply these rules automatically, so a mismatch is caught before you fly — usually too late to fix.