What is an ICAO airport code?

An ICAO code is a unique 4-letter identifier the International Civil Aviation Organization assigns to airports and aerodromes. They are used in flight plans, air traffic control, and aviation databases. EGLL, for example, is London Heathrow.

How is an ICAO code different from an IATA code?

IATA codes are 3 letters and are used for passenger-facing things like tickets and baggage tags. ICAO codes are 4 letters and are used operationally by pilots and controllers. London Heathrow is LHR in IATA and EGLL in ICAO.

What does the first letter of an ICAO code mean?

The first letter (or first two) encodes a world region. K covers the contiguous United States, E northern Europe, L southern Europe, R East Asia, and Y Australia. This lets controllers infer a rough location from the code alone.

Does this tool cover every airport in the world?

No. It uses a curated offline set of major international airports so it works instantly with no network call. Smaller or regional airfields may not appear. For an exhaustive list consult the official ICAO Doc 7910 location indicators.

Is my search sent anywhere?

No. The lookup runs entirely in your browser against a built-in table. Nothing you type is transmitted to any server.

What is the ICAO Airport Code Lookup?

Search ICAO 4-letter airport identifiers used in flight plans and air traffic control. Enter a code, airport name, or city to find the matching airport, its IATA code, location, and country from a curated reference set. It runs free in your browser on Gera Tools, with nothing uploaded.

ICAO Airport Code Lookup

Name: ICAO Airport Code Lookup
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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The International Civil Aviation Organization assigns every airport a unique four-letter ICAO identifier. Unlike the familiar three-letter IATA codes printed on boarding passes, ICAO codes are what pilots and air traffic controllers use in flight plans and clearances. This tool searches a curated set of major airports by ICAO code, IATA code, name, or city.

How ICAO codes are structured

Each ICAO code follows a two-level regional scheme encoded directly in its letters:

First letter — world region:

Prefix	Region
E	Northern Europe (Scandinavia, UK, Germany, etc.)
K	Contiguous United States
L	Southern Europe and Mediterranean
R	East Asia (Japan, Korea, Philippines)
Y	Australia
Z	China and Mongolia
F	Sub-Saharan Africa
O	Pakistan, Afghanistan, Gulf states

Second letter — country or sub-region within that group:

Within E, for example, G means United Kingdom, D means Germany, H means Finland. So EGLL = E (N. Europe) + G (UK) + LL (Heathrow’s local identifier).

This structure means that air traffic controllers can infer a rough location from the code alone, which matters when reading flight plans and NOTAM information.

ICAO versus IATA codes

These two systems serve different communities:

System	Length	Used for
IATA	3 letters	Passenger tickets, baggage, booking systems
ICAO	4 letters	Flight plans, ATC, pilot charts, weather reports

The same airport carries both codes, and they are often similar but not identical. London Heathrow: IATA is LHR, ICAO is EGLL. Paris Charles de Gaulle: IATA is CDG, ICAO is LFPG. A few airports have matching ICAO and IATA substrings by coincidence; most do not.

When you need the ICAO code

Filing a VFR or IFR flight plan — ICAO identifiers are mandatory in the ICAO flight plan form.
Reading METARs, TAFs and NOTAMs — these use the 4-letter ICAO code, not the 3-letter IATA code.
Configuring flight simulation software and avionics databases.
ATC phraseology training and study.

Searching this tool

The lookup matches against ICAO code, IATA code, airport name, city, and country. Useful searches:

Type EGLL to get Heathrow directly.
Type LHR (IATA) to find the ICAO code.
Type Germany to browse major German airports.
Type Kennedy to find JFK by partial name.

Because this tool uses a curated offline dataset of major commercial airports, very small airfields, heliports, and military-only aerodromes may not appear. For the exhaustive official list, consult ICAO Doc 7910 (Location Indicators), which covers tens of thousands of designators worldwide.