IATA City Code Validator

IATA city (metropolitan) code: one code for a multi-airport city

An IATA metropolitan area code is a three-letter code that represents a city served by more than one airport, rather than a single airport. NYC covers JFK, LaGuardia and Newark; LON covers Heathrow, Gatwick, Stansted, City and Luton; PAR covers Charles de Gaulle and Orly. Searching a flight by the city code returns options across all the city's airports. This tool checks the 3-letter format and recognises the best-known city codes.

The distinction trips up a lot of integrations: a city code is not an airport code, even though both are three uppercase letters. Some cities even have a city code that differs from any of their airports (e.g. NYC isn't itself an airport).

City code vs airport code

• City code: LON, NYC, TYO, MOW — search all airports of the metro area.
• Airport code: LHR, JFK, HND, SVO — one specific airport.
• Single-airport cities: where a city has one airport, the city code often equals the airport code (e.g. SIN, BKK).

Where it matters

• Flexible search: "fly to London" → LON shows the cheapest option across five airports.
• Fare construction: GDS and pricing engines distinguish city vs airport for fare rules.
• Data joins: matching bookings to airports requires expanding a city code to its member airports.
• Mock data / testing: validating that a code is a recognised metro code, not an airport.

Common pitfalls

• Same shape, different meaning: SAO (São Paulo metro) vs GRU (one airport) — don't treat them as interchangeable.
• Not every city has one: city codes exist mainly for multi-airport metros.
• Booking quirks: a city code can include a less convenient airport you didn't intend.
• Format ≠ exists: three letters pass the regex; a lookup confirms it's a real metro code.

FAQ

Should I search by city or airport code? City code for the cheapest fare to a metro area; airport code when you must use a specific airport.

Why doesn't every airport have a city code? Single-airport cities don't need one — the airport code already represents the city.

Is NYC an airport? No — it's the metropolitan code for New York, expanding to JFK, LGA and EWR.