What is the passport six-month rule?

Many countries require your passport to remain valid for six months beyond your arrival or planned departure, and the enforcement happens earlier than people expect: airlines check at the departure gate and will deny boarding, since they are fined for delivering inadmissible passengers. A passport with five months left can therefore end a trip at check-in, valid though it technically is.

The rule varies by destination, six months for much of Asia, the Middle East, and South America, three months beyond departure for Europe's Schengen area, and a handful of countries accept validity through the stay. The State Department's country pages list each requirement, and checking them is a two-minute task.

Practical translation: treat a passport as expired at the nine-month mark and renew. Routine renewal takes weeks, US passports are valid ten years for adults but only five for children, and blank pages matter for some visas too.