From the records, it appears that football in Koper was played as early as in the 1920s, but officially, the club took the name NK Koper in 1955, when it was formed by the merger of two football teams: Aurora and Meduza. The club played under this name in different Yugoslav leagues until 1991 and was one of the most successful Slovenian clubs. After Slovenia became independent, the club started to play in the Slovenian PrvaLiga and Slovenian Second League. At the beginning of the 1990s, the club was achieving mid-table success. By the end of the 1990s, the club had been relegated to the second division twice, had serious financial problems and renamed itself to FC Koper, thereby avoiding the necessity of paying off its debts. With the advent of the new millennium, FC Koper consistently achieved positions in the upper half of the table. In the 2003–04 season, they were playing in a European competition for the first time since 1991: the UEFA Intertoto Cup. Two years of mid-table anonymity and significant financial difficulties followed, in part because the former owner, Georg Suban, left substantial debts to the club and took half of the team with him when he moved to the other Slovenian PrvaLiga team Mura. The fans took control of the club and tried to improve its finances to save it from going bankrupt and disappearing like three other major Slovenian clubs, with reasonable success. In the 2005–06 season, Mladen Rudonja returned to the club and brought with him the Serbian-American businessman Milan Mandarić, who paid off all the remaining debts. After the first half of the season, before the arrival of the new patron, Koper was battling against relegation, but in the second part of the season, with a new coach, Milivoj Bračun, the club started an unbeaten run that led them to reach the third place in the Slovenian PrvaLiga and to win the Slovenian Cup for the first time, FC Koper's first trophy since the Slovenian independence from Yugoslavia. This also qualified the team to play in the UEFA Cup qualifying rounds in the 2006–07 season. The following seasons were more difficult, with the club narrowly avoiding relegation in 2009. In the 2009–10 season, the team was expanded and, under the leadership of veteran playmaker/director-of-football Miran Pavlin eventually won the Slovenian league championship for the first time, winning a place in the UEFA Champions League qualifiers, where they were defeated by Dinamo Zagreb 5–4 on aggregate. In the aftermath, Pavlin left the club. Following the 2016–17 season, Koper failed to obtain a competition licence and was excluded from the Slovenian top division.
Name changes
1920: Formed as Circolo sportivo Capodistria
1928: Renamed Unione sportiva Capodistriana
1946: Renamed Aurora Koper
1955: Fusion from Aurora Koper and Meduza Koper to NK Koper
Bonifika Stadium is the team's home ground, which is named after the area where it is situated in the town of Koper. The stadium was built in 1948. In 2010 the stadium underwent a major reconstruction and its current capacity is 4,047 seats.