The Estadio de La Cartuja will host an all-Basque final after Athletic Club advanced past Granada on away goals on Thursday night.
Real Sociedad booked their place following a 3-1 win on aggregate against Mirandes one night before, yet Athletic will now head into the final looking to make amends for the last few times they have reached this stage of the competition.
The meeting between Athletic and La Real will be the first occasion that the Basque derby has occurred in the Copa final, and it probably won't be the last time either.
A Copa final between two Basque teams has not happened since 1927, when Real Union faced Arenas Club in Zaragoza, a game Real Union won 1-0.
Since Athletic last lifted the Copa in the 1983/84 season, they have lost to Atletico Madrid (1984/85) and Barcelona (2008/09, 2011/12 and 2014/15) on three occasions on the big stage.