Athletic Club have won a total of 24 Copa del Reys, despite not having won one since 1984.
These are the years they've won it:
Copa del Rey (24): 1903, 1904, 1910, 1911, 1914, 1915, 1916, 1921, 1923, 1930, 1931, 1932, 1933, 1943, 1944, 1944–45, 1949–50, 1955, 1956, 1958, 1969, 1972–73...