The ICAO airport code or location indicator is a four-letter

code In communications and information processing, code is a system of rules to convert information—such as a letter, word, sound, image, or gesture—into another form, sometimes shortened or secret, for communication through a communicati ...

designating

aerodrome An aerodrome, airfield, or airstrip is a location from which aircraft flight operations take place, regardless of whether they involve air cargo, passengers, or neither, and regardless of whether it is for public or private use. Aerodromes inc ...

s around the world. These codes, as defined by the

International Civil Aviation Organization The International Civil Aviation Organization (ICAO ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international sch ...

and published quarterly in ICAO Document 7910: ''Location Indicators'', are used by

air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...

and airline operations such as flight planning. ICAO codes are also used to identify other aviation facilities such as

weather station A weather station is a facility, either on land or sea, with instruments and equipment for measuring atmosphere of Earth, atmospheric conditions to provide information for weather forecasting, weather forecasts and to study the weather and clima ...

s, international flight service stations, or area control centers (and by extension their flight information regions), regardless of whether they are located at airports.

History

The recommendations for ICAO airport codes were adopted on 24 March 1959, and came into force on 1 October the same year.

ICAO codes versus IATA codes

ICAO codes are separate and different from IATA codes, the latter of which have three letters and are generally used for

airline timetable Airline timetables are printed pamphlets or folders that many airlines have traditionally used to inform passengers of several different things, such as schedules, fleet, security, in-flight entertainment, food menus, baggage weight restrictions, ...

s, reservations, and

baggage Baggage, or luggage, consists of bags, cases, and containers which hold a traveler's personal articles while the traveler is in transit. A modern traveler can be expected to have packages containing clothing, toiletries, small possessions, tr ...

tags. For example, the IATA code for

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

's Heathrow Airport is LHR and its ICAO code is EGLL. IATA codes are used by flight-tracking services such as FlightAware. In general IATA codes are usually derived from the name of the airport or the city it serves, while ICAO codes are distributed by region and country. Far more

s (in the broad sense) have ICAO codes than IATA codes, which are sometimes assigned to railway stations as well. The selection of ICAO codes is partly delegated to authorities in each country, while IATA codes, which have no geographic structure, must be decided centrally by IATA.

Structure

The first one or two letters of the ICAO code indicate the country; the remaining letters identify the airport. For example, the ICAO code for Heathrow International Airport in London, is EGLL, with EG reflecting that it is based in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

. By contrast, IATA codes do not provide geographic reference. For example, LHR, representing Heathrow, does not enable one to deduce the location of the airport LHV with any greater certainty; it is William T. Piper Memorial Airport in Lock Haven, Pennsylvania in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. There are a few exceptions to the regional structure of the ICAO code for political or administrative reasons: * RAF Mount Pleasant air base in the

Falkland Islands The Falkland Islands (; ), commonly referred to as The Falklands, is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and from Cape Dub ...

, for instance, is assigned the ICAO code EGYP as though it were in the United Kingdom, but nearby civilian Port Stanley Airport is assigned SFAL, consistent with

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. *

Saint Pierre and Miquelon Saint Pierre and Miquelon ( ), officially the Territorial Collectivity of Saint Pierre and Miquelon (), is a self-governing territorial overseas collectivity of France in the northwestern Atlantic Ocean, located near the Canada, Canadian prov ...

is controlled by France, and airports there are assigned LFxx as though they were in Europe. *

Kosovo Kosovo, officially the Republic of Kosovo, is a landlocked country in Southeast Europe with International recognition of Kosovo, partial diplomatic recognition. It is bordered by Albania to the southwest, Montenegro to the west, Serbia to the ...

is assigned the code BKxx grouping it with

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

and

Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

rather than its geographical neighbors which have Lxxx (described below). * Jerusalem International Airport was assigned both LLJR (its Israeli persona) as well as OJJR (its Jordanian persona), but the airport itself fell into disuse. Western Sydney Airport, due to open in 2026 has the ICAO code YSWS. In Australia, the second letter is usually linked to the airport's

FIR Firs are evergreen coniferous trees belonging to the genus ''Abies'' () in the family Pinaceae. There are approximately 48–65 extant species, found on mountains throughout much of North and Central America, Eurasia, and North Africa. The genu ...

. However, Sydney's FIR has been non-existent since the introduction of TAAATS. In the contiguous United States and Canada, many airports have ICAO codes that are simply copies of their three-letter

IATA The International Air Transport Association (IATA ) is an airline trade association founded in 1945. IATA has been described as a cartel since, in addition to setting technical standards for airlines, IATA also organized tariff conferences tha ...

codes, with the geographical prefix added on (e.g., YEG and CYEG both refer to Edmonton International Airport, while IAD and KIAD both refer to Washington Dulles International Airport). This similarity does not extend to

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

(PAxx),

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

(PHxx), or U.S. territories. Kahului Airport on

Maui Maui (; Hawaiian language, Hawaiian: ) is the second largest island in the Hawaiian archipelago, at 727.2 square miles (1,883 km2). It is the List of islands of the United States by area, 17th-largest in the United States. Maui is one of ...

, for instance, has an IATA code of OGG and an ICAO code of PHOG. ICAO airport codes do not begin with I or J or X or Q, though the Jezero Crater on

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

is assigned the special ICAO code JZRO. Codes beginning with I (Ixx and Ixxx) are often used for navigational aids such as radio beacons, while the

Q code The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an Operating signals, operating signal initially developed for commercial radiotelegraphy, radiotelegraph communication and later adopted b ...

is reserved for international radiocommunications and non-geographical special use. In

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

, the Latin letter X, or its Morse/ Baudot Cyrillic equivalent Ь, are used to designate government, military, and experimental aviation airfields in internal airfield codes similar in structure and purpose to ICAO codes but not used internationally. ZZZZ is a pseudo-code, used in

flight plan Flight plans are documents filed by a aviator, pilot or flight dispatcher with the local Air Navigation Service Provider (e.g., the Federal Aviation Administration, FAA in the United States) prior to departure which indicate the plane's planned ...

s for aerodromes with no ICAO code assigned. ICAO codes are sometimes updated. Johannesburg Airport in

Johannesburg Johannesburg ( , , ; Zulu language, Zulu and Xhosa language, Xhosa: eGoli ) (colloquially known as Jozi, Joburg, Jo'burg or "The City of Gold") is the most populous city in South Africa. With 5,538,596 people in the City of Johannesburg alon ...

, South Africa, for instance, was formerly known as Jan Smuts International Airport, with code FAJS. When the airport was renamed O. R. Tambo International Airport, its ICAO code was updated to FAOR. Some airports have two ICAO codes, usually when an airport is shared by civilian and military users.

Frankfurt Airport Frankfurt Airport ( ) , is Germany's busiest international airport by passenger numbers, located in Frankfurt, Germany's fifth-largest city. Its official name according to the German Aeronautical Information Publication is Frankfurt Main Airpor ...

Frankfurt Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the forela ...

, Germany, for instance, has been assigned ICAO code EDDF while Rhein-Main Air Base was assigned ICAO code EDAF until its closure. Sion Airport in Switzerland has code LSGS while its military facilities have the ICAO code LSMS. Brussels Airport in

Brussels Brussels, officially the Brussels-Capital Region, (All text and all but one graphic show the English name as Brussels-Capital Region.) is a Communities, regions and language areas of Belgium#Regions, region of Belgium comprising #Municipalit ...

, Belgium, has the ICAO code EBBR for its civilian facilities, and Melsbroek Air Base has been assigned ICAO code EBMB, even though the two airports share runways and ground and air control facilities.

Pseudo ICAO-codes

In small countries like Belgium or the Netherlands, almost all aerodromes have an ICAO code. For larger countries like the UK or Germany this is not feasible, given the limited number of letter codes. Some countries have addressed this issue by introducing a scheme of sub-ICAO aerodrome codes; France, for example, assigns pseudo ICAO codes in the style ''LFddnn'', where ''dd'' indicates the department while ''nn'' is a sequential counter. The French Federation of Ultralight Motorized Gliders was formally named the keeper of these codes. Aerodrome de Torreilles in France, for instance, has code LF6651. In Antarctica many aerodromes have pseudo ICAO-codes with AT and two digits, while others have proper codes from countries performing air control such as NZ for

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

Prefixes

References

External links

* – for areas served by several airports * – relating to particular airports
International Civil Aviation Organization
(official site)
ICAO Doc 7910

ICAO Free World Airport and Runway Map
(ICAO official site)
Airport IATA/ICAO Designator / Code Database Search
(from Aviation Codes Central Web Site – Regular Updates) * {{List of airports Country codes Geocodes Location codes