[2] The first official match played by Opatija was on May 14, 1911, in Sušak, competing with the football section of that town's Sokol.

[citation needed] The club changes its name again in 1919 to Hajduk and back to Športski klub Opatija in 1921, the city being now part of the Kingdom of Italy and its authorities pushing for the dropping of the "Slavic" prefix.

Since then, NK Opatija has played in the regional league, which has taken various forms and names, with more or less success.

[citation needed] In the 1950s and in the first half of the 1960s, Opatija competed in the sub-federal Jugoslav league.

[citation needed] After the Croatian independence and since 1992, the club started competing in the III.

[9] Key Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.