Airports and airport choice · Explainer
Airport codes explained: IATA, ICAO and city codes
What the three-letter and four-letter codes on tickets and maps mean, who assigns them, and which one to type when you search.
By AMZBooking EditorialPublished 3 min read
Awaiting review by a named editor
In short
An IATA airport code is the three-letter code on tickets, timetables and flight searches, such as LHR. An ICAO code is a four-letter indicator used mainly by air-traffic control and flight planning, such as EGLL. A city code such as LON groups the airports that serve one city. Search with a city code to compare all of them, and with an airport code when you know which one you want.
Key facts
- Airports in our data with an IATA code and scheduled flights[1] source
- 3,244
- Countries and territories they are in[1–2] sources
- 233
- Of those airports, share with an ICAO code recorded[1–2] sources
- 100%
- City codes AMZBooking search offers[3] source
- 18
Three kinds of code
You will meet three kinds of airport code when you plan a trip. They come from different organisations and do different jobs.
| Code | Looks like | Mainly used for | Example |
|---|---|---|---|
| IATA airport code | Three letters | Tickets, timetables, bag tags and flight searches | LHR — London Heathrow Airport |
| ICAO airport code | Four letters | Air-traffic control and flight planning | EGLL — London Heathrow Airport |
| IATA city code | Three letters | Searching every airport of a city at once | LON — 6 London airports |
IATA airport codes
The International Air Transport Association (IATA) assigns three-letter location codes and publishes them through its code search and its Location Identifiers directory. They are the codes you see on boarding passes and bag tags, and the ones flight searches understand.[4] source
A code often hints at the place it serves, but not always. Of the 3,194 airports in our data with a recorded town or city, 68% have a code that starts with the same letter as that town’s name, and only 11% use its first three letters. Codes can preserve an older name, or the name of the airport rather than the city.[1–2] sources
ICAO codes and what their first letters mean
The International Civil Aviation Organization (ICAO) publishes four-letter location indicators in its Doc 7910. The first letter identifies a region of the world and the first two letters usually narrow it to a country, so neighbouring airports often share a prefix.[5] source
In our data, ICAO codes start with 22 different letters; for example, all 430 airports in our data whose ICAO code starts with K are in the United States. ICAO codes rarely matter when you book, but they appear in flight-tracking apps and on our airport guides.[1–2] sources
City codes: every airport of a city in one search
Some cities have an IATA city code covering several airports — for example NYC for New York (JFK, EWR, LGA). In AMZBooking search they appear as “all airports” choices. Our list of which airports each city code covers is an editorial list we keep for search convenience and review before we state it as fact.[3] source
| City code | City | Airports it covers |
|---|---|---|
| NYC | New York | JFK, EWR, LGA |
| LON | London | LHR, LGW, STN, LTN, LCY, SEN |
| PAR | Paris | CDG, ORY, BVA |
| TYO | Tokyo | HND, NRT |
| CHI | Chicago | ORD, MDW |
| WAS | Washington | IAD, DCA, BWI |
Which code to type when you search
Flexible about the airport?
Use the city code, so the results compare every airport it covers (searching by city code).
Know where you start or finish?
Check which airports are nearest that place with the nearby airports finder, then search those airports.
Already decided?
Use the airport code to keep the results to that airport only.
What a code doesn’t tell you
- How far the airport is from the city centre — or from where you are actually going.
- How big it is, which airlines use it, or how often they fly.
- Whether a city code’s airports are equally convenient: they can be on opposite sides of a metropolitan area.
For those questions, start with choosing between nearby airports and the airport pages it links to.
How to look up a code
- Our airport guides list each airport’s IATA and ICAO codes with their sources.
- For example, the London Heathrow Airport guide shows both of its codes and its nearby airports.
- IATA’s own code search covers airline and location codes (source).
- Definitions of every code type are in our travel glossary.
Sources
- 1.
OurAirports open data — airports and runways — OurAirports (David Megginson and contributors)
Licensed or open structured datasetRead Licence: Public Domain
Airports filtered to: type in (large_airport, medium_airport) AND scheduled_service = 'yes' AND iata_code ~ /^[A-Z]{3}$/ (3,244 records).
- 2.
AMZBooking dataset statistics method — AMZBooking
AMZBooking calculation (documented method)Read
Counts, rankings and extremes over the cited datasets; rankings order one measurable attribute.
- 3.
AMZBooking city-code list (editorial) — AMZBooking editorial team
AMZBooking calculation (documented method)Read
Which airports each IATA city code covers, as used by AMZBooking search. Editorial; reviewed before stated as fact.
- 4.
Airline and Location Code Search — International Air Transport Association (IATA)
Standards body or authoritative institutionLocated Not yet verified by an editor
IATA’s public lookup of 2-letter airline and 3-letter location codes; IATA publishes the full sets in its Airline Coding Directory and Location Identifiers.
- 5.
Location Indicators (Doc 7910) — International Civil Aviation Organization (ICAO)
Government or official agencyLocated Not yet verified by an editor
ICAO’s publication listing four-letter location indicators and, where available, the corresponding three-letter IATA identifiers.
How this article was made
Written by the AMZBooking editorial team with AI assistance. Numbers come from the datasets and methods listed above, calculated when the site is built, and every claim cites a source. It has not yet been reviewed by a named editor, so it is not offered to search engines yet. Read our editorial policy.
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