Swansea City Association Football Club ( SWON-zee; Welsh: Clwb Pêl-droed Dinas Abertawe) is a Welsh professional football club based in Swansea, Wales. It competes in the EFL Championship, the second tier of the English football league system. Swansea have played their home matches at the Swansea.com Stadium (formerly known as the Liberty Stadium) since 2005, having previously played at the Vetch Field since the club was founded.

The club was founded in 1912 as Swansea Town and entered into the Southern League, winning the Welsh Cup in their debut season. They were admitted into the Football League in 1920 and won the Third Division South title in 1924–25. They again won the Third Division South title in 1948–49, having been relegated two years previously. They fell into the Fourth Division after relegations in 1965 and 1967. The club changed their name to Swansea City in 1969 to reflect Swansea's new status as a city. They were promoted at the end of the 1969–70 season.

Swansea won three promotions in four seasons to reach the First Division in 1981. They finished sixth the following season, a club record. The club suffered a relegation the season after, returning to the Fourth Division by 1986 and then narrowly avoiding relegation to the Conference in 2003. In 2011, they were promoted to the Premier League and won the League Cup two years later, beating Bradford City 5–0 in the final. It was the competition's highest ever winning margin for the final, with Swansea winning the first major trophy in the club's history and qualifying for the 2013–14 UEFA Europa League. The club was relegated from the Premier League at the end of the 2017–18 season.

The club's climb from the fourth division of English football to the top division is chronicled in the 2014 film, Jack to a King – The Swansea Story. The Swansea City Supporters Trust continues to own shares in the club; their involvement was hailed by Supporters Direct in 2012 as \"the most high profile example of the involvement of a supporters' trust in the direct running of a club\".