Aviation & Real-World Flying 4 min read

How do I find an airport’s ICAO code?

Ian Stephens
In short

Find an airport's ICAO code by name, city or IATA code, verify the correct result, and solve missing or outdated code problems.

To find an airport’s ICAO code, search its full name, city or three-letter IATA code in a reliable airport database, then confirm the four-letter result against a current chart or official flight-information source. In real-world aviation and flight simulation, use the ICAO location indicator—not the airline-style IATA code—whenever one exists.

What is the fastest way to find an airport ICAO code?

The quickest method is to search an airport database and verify that the result matches the intended location.

  1. Search broadly. Enter the airport name, nearby city, IATA code or part of the name in our searchable World Airport Database.
  2. Check the airport identity. Compare the country, municipality, coordinates and runway information. Airports with similar names may be hundreds of miles apart, while an airport’s official name may differ from the city it serves.
  3. Read the ICAO field. The official ICAO location indicator is four letters, such as KLAX for Los Angeles International or EGLL for London Heathrow.
  4. Verify time-sensitive information. For real-world planning, confirm the code against a current airport chart or national aeronautical information publication. Our guide to finding suitable airport charts for a flight simulator explains the available chart types.

How are ICAO, IATA and local airport codes different?

An airport’s ICAO code is a four-letter operational location indicator; IATA and national identifiers belong to different coding systems.

Code systemUsual formatMain useHeathrow example
ICAO location indicatorFour lettersATC, flight planning, weather, charts and simulatorsEGLL
IATA codeThree lettersTickets, baggage and passenger informationLHR
National or local identifierVaries; may include digitsCountry-specific records and smaller aerodromesVaries by country

Simulator menus sometimes call every airport identifier an ID or Ident. Do not assume every four-character entry is an official ICAO code: simulators and add-on scenery can use internal identifiers for airports that lack one. Aircraft type designators such as A320 are part of a separate ICAO coding system.

Can I convert an IATA code into an ICAO code?

There is no universal formula for converting an IATA airport code into an ICAO code.

Many airports in the contiguous United States use K followed by the familiar three-letter identifier, so LAX becomes KLAX. That shortcut fails in Alaska, Hawaii, US territories and cases where the IATA and national identifiers differ. Outside the United States, codes such as EGLL have no direct letter-by-letter relationship with LHR.

Always perform a database lookup rather than guessing from a country prefix.

What if an airport has no ICAO code?

Some small, private or specialist aerodromes have no assigned ICAO location indicator.

Use the published national or local identifier where the simulator or planning tool accepts it; otherwise, search by name or coordinates. Never manufacture a four-letter code by adding a regional prefix, because that could identify a different location.

On an ICAO flight plan, ZZZZ means that the departure or destination has no assigned location indicator, with the aerodrome details supplied under DEP/ or DEST/ in Item 18. ZZZZ is a placeholder, not the airport’s code and not something to search in a simulator.

Why does a valid ICAO code not work in my simulator?

A valid real-world ICAO code may fail because of a typing error, an older simulator database, a renamed or closed airport, or an aerodrome omitted from the simulator.

  • Check for transposed letters and confusion between letters such as O and I. Official ICAO location indicators contain four letters, not digits.
  • Search using the airport’s IATA code, full name, former name, nearby city or coordinates.
  • Compare the simulator’s airport position and runway layout with current information; an old identifier may still point to legacy scenery.
  • Check whether an installed scenery package uses a replacement or simulator-specific identifier.

In Microsoft Flight Simulator, an exact ICAO search still cannot display an airport that is absent from the installed airport database. If the code works elsewhere but produces no result, follow our troubleshooting steps for an airport missing from Microsoft Flight Simulator.

AI Assistant New

Still stuck? Ask Fly Away

Ask Fly Away is our AI flight-sim assistant. Ask your exact question and get a direct, step-by-step answer in seconds — free to try.

Ask Fly Away Free preview · unlimited for PRO members