In 1964, Arka merged with "Doker Gdynia", to form "Maritime United Sports Club (Morski Związkowy Klub Sportowy, MZKS) Gdynia". In 1972, its name was changed into Arka. Two years later Arka won promotion to the Ekstraklasa. Relegated after one year, Arka returned to the top level in 1976. In 1979 Arka, managed by Czesław Boguszewicz, became the first team from Polish Baltic Sea coast to win the Polish Cup. In the final game, which took place in Lublin, Arka beat Wisła Kraków 2–1. In its UEFA Cup Winners' Cup debut, Arka lost to Bulgarian side PFC Beroe Stara Zagora (3–2, 0–2).