Yes. If you are booking an international flight on LATAM Airlines, you must enter your passport number during the booking process, and it must match the passport you will physically carry. For domestic flights within a single country, a passport number is generally not required, but LATAM may still ask for a government ID number. The requirement is driven by government data laws, not by an airline preference, and understanding why removes most of the confusion.
The mechanism: why the airline collects passport data at booking
A passport number is a government identifier, and airlines collect it because border agencies legally require advance passenger data. When you book an international itinerary, LATAM transmits a portion of your booking record to the destination and transit countries through systems such as APIS (Advance Passenger Information System) and, in the United States, the Secure Flight program run by the Transportation Security Administration. The airline is acting as a data conduit, not a data owner.
The reason the number is captured at booking rather than at the gate is structural. Under the International Civil Aviation Organization's Convention on International Civil Aviation, commonly called the Chicago Convention, each passenger must be documented before boarding an international flight (International Civil Aviation Organization, Annex 9). Border authorities want the manifest hours before departure so they can screen names against watchlists and validate travel documents.
Two data fields travel together and cause most of the friction. The passport number is the primary identifier that authorities use to match you to a document, and the expiration date is the field that triggers alerts if a passport will be invalid during the trip. A minor field mismatch such as a transposed digit can cause a boarding denial even if the passport itself is valid.
One plain-language way to frame the mechanism: the airline is filing an electronic version of your passport with the destination country before you fly, and the passport number is the record locator for that filing.
Quantified context: how much data and how far ahead
Keeping numbers in perspective helps you judge how quickly you need to act. The Passenger Name Record that LATAM creates for an international booking typically holds dozens of data points, of which the passport number and country of issuance are two of the most heavily screened. The registration window is determined by government directives, not by the airline; for U.S.-bound flights, the airline must transmit manifest data in the window before departure, with updates required if the manifest changes before the flight.
The practical implication is that the passport number is not cosmetic. If LATAM has an outdated number on file, your booking is not automatically corrected by presenting the new passport at the counter. The airline's passenger data flows through automated systems, and a mismatch can flag you for secondary screening or, rarely, denial of boarding at the carrier's discretion. That is why correcting the number before departure is safer than resolving it at check-in.
The date reference matters as much as the digit string. Many countries require that your passport remain valid for a set period beyond your arrival date, commonly six months, though the exact requirement varies by destination and can change. LATAM may prompt for the expiration date partly to surface this requirement to you.
Edge cases: when the rule bends
The strict "passport required" answer applies to international cross-border travel. Domestic flights within a single country are governed by that country's identification rules, not border screening, which is why the passport number is often optional or replaced by a national ID number.
There are several situations where the booking flow becomes less obvious.
Dual citizens: you should enter the passport you will present at check-in, which may differ from the one you used previously. Name changes: a new married or legal name requires updating the passport data, not just the reservation name. Passport renewals: a new passport number must be entered manually, because the airline does not auto-link renewals. Infants and children: minors need their own passport number for international travel, and an adult's passport cannot substitute. Permanent residents and visa holders: the passport number is still the primary field, with visa or residency data entered separately. Codeshare and interline flights: the operating carrier may request the data directly even if you booked through LATAM.
Red-flag warnings are worth stating plainly:
Do not leave the passport number blank and expect to fix it at the airport. Do not enter a passport that will expire before or shortly after your return date without checking the destination's validity rule. Do not assume a name change on the ticket updates the passport field. Do not rely on a printout of your booking as a substitute for a corrected passenger record.
Misconceptions and the counterintuitive detail
The most common misconception is that the passport number is an airline security question. It is not. The airline collects it because the destination country's border authority demands it. When people ask why LATAM needs a passport number for a flight that stays within one country or for a flight where a national ID would work, the answer is that the booking system applies international rules based on the itinerary's border crossings, not on the nationality of the traveler.
A second misconception is that the passport number and the visa number are interchangeable. They are not. The passport number is the document number for your travel document, and visa or authorization numbers are separate fields keyed to that document. A traveler who enters the visa number where the passport number belongs creates a record that will not match the physical document.
The counterintuitive detail is this: the passport number you enter does not need to be your most recently issued passport at the moment of booking, but it must be the passport you carry on the day of travel. Travelers who book months ahead sometimes enter a passport that expires during the trip and later renew. The airline record still points to the old document unless the change is made. The system does not reconcile the two automatically.
A professional caveat from airline operations: the requirement also depends on the ticketing carrier's data handling. If you book a LATAM-marketed flight that is operated by a partner airline, the passport data may be requested by either carrier, and one system may not propagate the correction to the other. Confirming the passport field in the checkout summary, and again when the booking is confirmed, is the safeguard.
Comparison table: passport data by itinerary type
| Itinerary type | Passport number generally required at booking? | What is typically required | Why |
|---|---|---|---|
| International flight to a foreign country | Yes | Passport number and expiration | Advance passenger data law |
| Domestic flight within home country | Usually no | National ID or driver's license | Domestic identity rules |
| International itinerary with a connection | Yes, for all segments | Passport matched to name | Transit country screening |
| Codeshare operated by a partner | Yes, often at ticketing and again at check-in | Passport data matching the ticket | Separate carrier systems |
| Flights to a country requiring six-month passport validity | Yes | Passport number plus expiration check | Destination entry rule |
The table's headline is that the requirement tracks the itinerary's border crossings, not the airline's preference. When in doubt, enter the passport and check that the number and expiration date match the document you will carry.
Timeline table: passport data over the booking life cycle
| Stage | What happens with the passport number | What you should do |
|---|---|---|
| Booking (months ahead) | You enter passport number and expiration | Match the document you will carry |
| Ticketing confirmation | Data attaches to your PNR | Re-check the summary on your confirmation |
| 72 hours before departure | Airline transmits manifest data | Confirm nothing changed; renew if needed |
| 24 hours before departure | Online check-in opens; data may be re-validated | Update the record if anything is wrong |
| Airport check-in | Agent scans the physical passport | Carry the exact document on file |
| Boarding gate | Document check against manifest | No changes at this stage |
The lifecycle shows that the most recoverable moment is before the manifest is transmitted. A wrong digit discovered weeks before the flight can be corrected through the booking or customer service. The same error discovered at the boarding gate is much harder to fix.
Practical actions: what to enter and when to verify
The simplest rule is to enter the passport number at booking whenever the itinerary crosses a border, and to verify three fields against the physical document: the number, the expiration date, and the name in the exact format the passport uses.
Concrete steps:
Book with the passport you will carry. If it is expiring within nine months, consider renewing before booking to avoid a validity shortfall. Confirm the passport number and expiration in the booking summary, then store the confirmation number. If you renew your passport after booking, update the number in your booking before the manifest is transmitted; do this once, then verify the update. For codeshare flights, verify the passport field with both carriers if both systems ask for it. Check destination validity rules before departure, especially for trips near a passport expiration date.
Limitations: what the airline flow cannot guarantee
The booking system collects data; it does not adjudicate your travel eligibility. It cannot confirm that your passport satisfies a destination's validity rule, that your name matches government records, or that a transit country will admit you. Visa and entry requirements remain your responsibility and can differ from the airline's checklist. If a passport number is required at booking, that is not a guarantee that all data will flow correctly across partner systems.
The passport number requirement can also vary by booking channel, and the exact prompts may change as data-handling regulations evolve. What is stable is the mechanism: international transport demands advance passenger data, and the passport number is the document key. That is why the answer to the keyword question is essentially yes for international LATAM reservations and no for pure domestic travel.
[This article is general educational information about airline booking data practices, not a legal opinion on immigration, border control, or travel document requirements. Airline systems and government entry rules change, and individual circumstances vary, so confirm the current requirements with LATAM Airlines and with the consulate or border authority of your destination before travel.]