Estrada FernándezThe final should have been played on April 18, 2020, but it was suspended due to the coronavirus pandemic, going on to be played on April 3, 2021, without spectators.
| 1 |  | Unai Simón | |||
| 4 |  | Iñigo Martínez | 62 | ||
| 5 |  | Yeray | |||
| 17 |  | Yuri | 93 | ||
| 10 |  | Muniain | |||
| 27 |  | Vencedor | 68 | ||
| 14 |  | Dani García | 76 | 35 | |
 | Berenguer | 76 | |||
| 18 |  | De Marcos | |||
| 22 |  | Raúl García | |||
| 9 |  | Williams |
| 1 |  | Remiro | |||
| 18 |  | Gorosabel | 93 | ||
| 24 |  | Le Normand | |||
| 5 |  | Zubeldia | |||
| 20 |  | Monreal | |||
| 8 |  | Merino | 71 | ||
| 36 |  | Zubimendi | |||
 | Silva | 85 | |||
| 10 |  | Oyarzabal | 63 | ||
| 7 |  | Portu | 88 | ||
| 19 |  | Isak | 88 |
Substitutes
| 21 |  | Capa | 93 | ||
| 16 |  | Vesga | 76 | ||
| 25 |  | Villalibre | 76 | ||
| 8 |  | Unai López | 68 | ||
| 3 |  | Nuñez | |||
| 19 |  | Ibai Gómez | |||
| 31 |  | Ezkieta | |||
| 15 |  | Lekue | |||
| 24 |  | Balenziaga |
| 6 |  | Elustondo | 93 | ||
| 16 |  | Guevara | 85 | ||
| 22 |  | Barrenetxea | 88 | ||
 | Carlos Fernández | 88 | |||
| 11 |  | Januzaj | |||
 | Ayesa | ||||
| 12 |  | Aihen Muñoz | |||
| 15 |  | Sagnan | |||
 | Bautista |
Managers
Milestones
Match #1 of Berenguer in King's Cup with club Athletic Club
Match #1 of Vencedor in King's Cup
Match #1 of Silva in King's Cup with club Real Sociedad
Match #1 of Zubimendi in King's Cup
Match #1 of Carlos Fernández in King's Cup with club Real Sociedad
Match #1 of Marcelino in King's Cup with club Athletic Club