Sydney Kingsford Smith International Airport officially opened on 9 January 1920, when aviator Nigel Love performed the first official flight from a leased patch of land in Mascot, a suburb just 8 kilometres south of the Sydney central business district. The site was originally held by the Kensington Race Club; the Commonwealth Government acquired it in 1923 and expanded it into a national airport the following year. Regular commercial services began in 1924. In 1936, the airport was renamed in honour of Sir Charles Kingsford Smith, the pioneering Australian aviator who had established a flying school there in 1928. It is one of the world's longest continuously operated commercial airports.

The airport sits beside Botany Bay, a geography that shapes its operations in concrete ways. Its longest runway, 16R/34L, extends into the bay and stretches 3,963 metres, making it the longest operational runway in Australia. The runway configuration was designed in 1945 by Keith Bradfield, whose father designed the Sydney Harbour Bridge. A legislated curfew under the Sydney Airport Curfew Act 1995 restricts most jet operations between 11 pm and 6 am, a constraint that distinguishes SYD from nearly every other major international hub in the region. The international terminal, Terminal 1, opened on 3 May 1970 and sits on the opposite side of the main runway from the domestic terminals, requiring passengers to transfer by bus or rail.

SYD is the primary hub for Qantas and a significant operating base for Virgin Australia and Jetstar. In the 2024-25 financial year, the airport handled approximately 41.8 million passengers. The Sydney-Melbourne corridor is one of the most-travelled city-pairs in the world. Internationally, Auckland and Singapore rank among its busiest routes. With roughly 320,000 aircraft movements per year and a hard cap of 80 movements per hour, SYD operates at the edge of its permitted capacity, a pressure point that has driven planning for a second Sydney airport at Badgerys Creek.