A passport series is a code printed on a passport that identifies the document’s type, production batch, or booklet inventory number, and what it means depends on the country that issued the passport. If you hold a U.S. passport, there is no field labeled “series” anywhere on the document. When a visa application or immigration form asks for one, enter your full passport number, or select “Does Not Apply” if that option is offered.
What the Term Actually Refers To
There is no single global definition. In Russia, the passport series is a distinct four-digit prefix printed separately from the six-digit passport number. The first two digits are a regional code; the second two indicate the year the booklet was produced. A Russian citizen always knows their series because it sits in its own labeled field.
U.S. passports work differently. The passport number is the primary identifier, and any batch or type information is embedded inside the number itself or elsewhere on the data page rather than broken out as a “series.” That’s why U.S. travelers so often stall on forms drafted with the Russian-style layout in mind.
What to Enter on a Form Asking for a U.S. Passport Series
Use your passport number. It’s the nine-character code in the top right corner of the data page (and repeated at the bottom of every page inside the booklet). If the form accepts “Does Not Apply” or “N/A,” that is also correct for a U.S. passport.
Watch out for a related field on the DS-160 nonimmigrant visa application: the passport book number, sometimes called the inventory control number or booklet number. This is not the same as your passport number. It’s a separate stock-tracking serial that some countries print on their passports, including France, Germany, Sweden, and several South American issuers. U.S. passports do not have one. If the DS-160 asks for it, select “Does Not Apply.”
How U.S. Passport Numbers Are Formatted
Older U.S. passports used a nine-digit numeric code. The Next Generation Passport, which the State Department began issuing in 2021, uses one letter followed by eight digits.1U.S. Department of State. Information about the Next Generation U.S. Passport
The State Department has not publicly said whether the leading letter encodes an issuing office, production batch, or document type. The Next Generation Passport also introduced a polycarbonate data page and laser-engraved personal information, both intended to make the booklet harder to tamper with.1U.S. Department of State. Information about the Next Generation U.S. Passport
One more detail matters if you carry both documents: the passport book and the passport card always have different numbers, even when issued to the same person. Passport cards have not been redesigned under the Next Generation program and use their own separate numbering.2U.S. Department of State. Statement Regarding A Valid Lost or Stolen US Passport or Card
The MRZ Document Type Code
The closest thing to a universal “passport series” is the two-character document type code at the start of the machine-readable zone (MRZ) on the bottom of the data page. The first character is always “P” for passport. The second character identifies the kind of passport.3International Civil Aviation Organization. Doc 9303 – Machine Readable Travel Documents – Part 4: Specifications for Machine Readable Passports (MRPs) and other TD3 Size MRTDs
The internationally standardized codes are:
- PP: National or ordinary passport
- PD: Diplomatic passport
- PO: Official or service passport
- PE: Emergency passport
- PR: Refugee passport
- PS: Stateless passport
- PM: Military passport
- PL: Laissez-passer passport
- PT: Alien or non-citizen passport
As of January 1, 2026, all newly issued passports must include this standardized second character. By 2028, every passport worldwide must comply, and older passports without the harmonized code must expire before 2038.3International Civil Aviation Organization. Doc 9303 – Machine Readable Travel Documents – Part 4: Specifications for Machine Readable Passports (MRPs) and other TD3 Size MRTDs
These codes let border control systems recognize what kind of passport is being scanned before an officer opens it. A diplomatic passport routes differently than an ordinary one, and the MRZ signals that instantly. Forms almost never ask travelers to enter this code, but if you ever see the phrase “document type” on an arrival form and are unsure, “P” for an ordinary passport is the safe answer for a standard U.S. book.
U.S. Passport Types and Internal Endorsement Series
The United States issues three passport colors: blue for regular passports, maroon for official government travel, and black for diplomatic use. Inside each book, the Foreign Affairs Manual assigns numbered endorsement series that identify the bearer’s status, such as a diplomat on assignment, a member of Congress, a Supreme Court Justice, or a military observer on a United Nations mission.4U.S. Department of State. Foreign Affairs Manual – Passport Endorsements
Regular passport holders don’t need to track these endorsement codes. They exist for internal government use and foreign diplomatic protocol. But they explain why “series” turns up in conversation about U.S. passports at all: it isn’t a single field, it’s a scattered set of codes and identifiers, each aimed at a different reader of the document.