Athletic Club, widely known outside Spain as Athletic Bilbao, was founded in 1898 in the Basque city of Bilbao and is one of only three clubs never to have been relegated from La Liga, alongside Real Madrid and Barcelona. Home matches are played at San Mamés, the modern stadium opened in 2013 that inherited the name and the "Cathedral" nickname of its predecessor.

The club has won eight Spanish league titles and stands second only to Barcelona in Copa del Rey victories, with 24 to its name, the most recent in 2024. It is best known for its cantera policy, in place for more than a century, of fielding only players born in or developed within the wider Basque Country.

Athletic competes in La Liga and has returned to European competition in recent seasons.