To enter Bali, a US passport must be valid for at least 6 months beyond your arrival date and have 2 blank pages. Both conditions are checked, and a traveler who does not meet them is refused entry. Check the expiry date and count the empty pages before you book flights, because renewing a passport takes longer than buying a ticket.
The six-month passport rule
Indonesia requires a visitor's passport to be valid for at least six months beyond the date of arrival. The State Department lists the requirement on its Indonesia page, and the US Consular Agency in Bali repeats it for all visitors to the island. A passport that is still valid on the day you land, but expires four months later, does not meet the rule.
Count from the day you land
The six months run from your arrival in Indonesia, so the date that matters is the one you land in Bali. A flight from the United States crosses the date line and lands on a later calendar date than it departs. Take your arrival date, add six months, and compare the result with the expiry date printed on your passport's photo page.
Why a close call is a bad idea
The US Consular Agency in Bali states the consequence plainly: Balinese immigration authorities will not allow you to enter the country if you do not meet the requirement. There is no fee that fixes a short passport at the border. If your passport is within a year of expiring, our advice is to renew it before you plan the trip.
The two blank pages rule
Indonesia also requires two blank pages in the passport, and the US Consular Agency in Bali adds a detail many travelers miss: the endorsement page at the back of a US passport does not count as a blank page. The two pages must be visa pages with nothing stamped or stuck on them.
How to count your pages
Open the passport and look for pages headed "Visas" that are completely empty. Pages headed "Endorsements" do not count toward the two. A page with a single small stamp in one corner is no longer blank. If you have traveled a great deal on this passport, do the count now instead of at the check-in desk.
If you are short of pages
A passport that has run out of visa pages has to be replaced, and that is done through the State Department's passport renewal process. Processing times change through the year, so check the State Department's passport pages for the current estimate and the expedited options before you set your travel dates.
What immigration asks to see on arrival
Indonesia's official visa finder lists the documents a US tourist presents to the immigration officer on arrival: a passport valid for at least six months and an outbound ticket from Indonesia. The passport rule and the ticket rule sit side by side in the same list, so prepare both.
The onward ticket
The outbound ticket is a ticket that leaves Indonesia, to any country. It should fall inside the stay your visa allows, which for the tourist visa is 30 days, extendable once for another 30 days. Keep the booking confirmation where you can show it without a data connection, such as a screenshot or a printout.
The arrival card uses the same passport
The arrival card that every traveler submits in the last 72 hours before landing asks for your passport details. Enter the number of the passport you will travel on. If you renew your passport after buying an e-VOA, the visa was issued against the old passport number, so renew first and buy the visa second.