The Basque derby, contested by Athletic Club and Real Sociedad, stands out in world football for its notably friendly rivalry. Supporters from both clubs traditionally mix in and around stadiums on matchdays, a rare sight for a local derby. Organised events, such as a 'kalijera' supporters' parade and a 'Bertso-derbia' singing contest, further foster this relaxed atmosphere.
While an inter-city rivalry exists between Bilbao and San Sebastián, a shared Basque identity and culture unite the fans. Athletic Club maintains a distinctive policy of only fielding players born in the Basque Country or trained at Basque clubs. Real Sociedad also had a similar policy until 1989.
Despite occasional instances of tension, particularly concerning player transfers between the clubs, the overall spirit of mutual respect prevails. This derby is often viewed as a celebration of coexistence and sporting respect.
