Sydney Kingsford Smith International Airport officially opened on 9 January 1920, when aviator Nigel Love performed the inaugural flight from a leased paddock in the suburb of Mascot, roughly 9 kilometres south of the Sydney central business district. It is one of the world's longest continuously operated commercial airports. The Commonwealth Government took ownership of the site after Love's lease expired in 1923, and regular commercial flights began in 1924. Gravel runways arrived in 1933. In 1936, the airport was renamed in honour of pioneering Australian aviator Sir Charles Kingsford Smith, famous for completing the first trans-Pacific flight.

The post-war decades transformed the site dramatically. The Cooks River was diverted between 1947 and 1953 to make room for paved runways, and the main north-south runway was later extended into Botany Bay, eventually becoming one of the longest commercial runways in the Southern Hemisphere. The international terminal, opened on 3 May 1970 by Queen Elizabeth II, replaced a temporary overseas facility and introduced the airport to the jet age; the first Boeing 747 arrived later that same year. A controversial third parallel runway, built on reclaimed land from Botany Bay, was completed in 1994, prompting the Australian Parliament to pass the Sydney Airport Curfew Act 1995, which prohibits jet operations between 11 pm and 6 am.

Today the airport operates 3 terminals across 907 hectares, with Terminal 1 handling all international traffic and Terminals 2 and 3 serving domestic routes. It is the primary hub for Qantas and a hub for Virgin Australia, and an operating base for Jetstar, serving 46 domestic and 43 international destinations directly. In 2024, the airport handled 41.4 million passengers. SYD is accessible by train in under 20 minutes from the city centre and remains the country's dominant aviation gateway, even as Western Sydney International Airport prepares to open in late 2026.