Kocaelispor (, ), is a Turkish professional football club based in İzmit, Kocaeli Province. Founded in 1966, the club competes in the Süper Lig, the top tier of the Turkish football league system. Kocaelispor plays its home matches at the 34,829-capacity Kocaeli Stadium, and its traditional colours are green and black.
Kocaelispor has spent several spells in the Süper Lig, most notably between 1980 and 1988, 1992 and 2003, and during the 2008–09 season. The club's highest league finish came in the 1992–93 season, when they placed fourth. Kocaelispor has won the Turkish Cup twice, in 1997 and 2002.
Nicknamed the Körfez'in Şimşekleri ( Thunderbolts of the Gulf), the club enjoys a strong local following in İzmit and the surrounding Kocaeli region. Their main rivalry is with Sakaryaspor, contested in the heated Körfez Derbisi ( Gulf Derby).
After a period of financial turmoil and successive relegations during the 2010s, Kocaelispor descended into the amateur leagues. However, a sustained rebuilding effort led to a series of promotions. In the 2023–24 season, they reached the play-offs after finishing sixth. The following year, they secured promotion to the Süper Lig with three matches remaining in the 2024–25 season, marking their return to the top division after a 16-year absence.
Baçspor had sold the plat for 283,000 Liras and had a new place in Baç district of İzmit; and begun to a new construction. In 1964, Baçspor club board planned to found a new team at professional level and compete in 2nd Division. However, federation regulation of that time was stating that it was required to compound at least 3 teams and have appropriate facilities. Then, in 1966, three teams which are Baçspor, İzmit Gençlik and Doğanspor had come together, combined and founded Kocaelispor. Three club boards had consensus on every subject and embraced the green and black as the club colours. Then, it had been held a club congress in common and the new club board had been elected. Kocaelispor had spent 175,000 Liras to gather their first squad ever to compete in 2nd Division in 1966.
Kocaelispor was promoted to the 1st Division for the first time in 1980. They competed 8 seasons consecutively until their relegation in 1988. However, during this phase, the club has relegated once in 1986–87 season and come back after a Turkish Council of State verdict.
The team was managed by Güvenç Kurtar, and the squad featured a number of notable and respected players. Fahrudin Omerović, a former substitute goalkeeper for the Yugoslavia national team, provided valuable experience in goal. Defenders Stevica Kuzmanovski and Mirko Mirković (who later acquired Turkish citizenship under the name Mert Meriç) strengthened the back line, bringing further quality from the Yugoslav football school.
In attack, Bülent Uygun played as a forward alongside Turkish international striker Saffet Sancaklı, forming a prolific offensive partnership. Uygun went on to become the league's top scorer while at Fenerbahçe, while Sancaklı initially transferred to Galatasaray before returning to Kocaelispor in 1995, later also joining Fenerbahçe. Other notable members of the squad included Bülent Baturman, Halil İbrahim Kara, Melih Erdem, and Ergun Kula, all of whom contributed to what is remembered as one of the most successful and celebrated seasons in Kocaelispor's history.
During the 2007–08 season, Kocaelispor were managed by three different coaches: Fuat Yaman (weeks 1–10), Kayhan Çubuklu (weeks 11–31), and Engin İpekoğlu (weeks 32–34). They returned to the Süper Lig as champions of the TFF First League, but consecutive relegations followed. The club was demoted to the TFF Second League in the 2010–11 season, and then to the fourth tier in 2011–12 after finishing last in the White Group of the Second League. Finally, they were relegated to the Turkish Regional Amateur League in 2014, after losing 1–0 away to İstanbulspor with four rounds remaining, concluding their season on 6 April 2014.
In the 2014–15 season, Kocaelispor competed with clubs such as Tekirdağspor, Çengelköyspor, and Arnavutköy Belediyespor for promotion to the TFF Third League. They led the league for several weeks but ultimately finished 4th in Group 11, with Tekirdağspor achieving promotion after 11 seasons. The following season, Kocaelispor won their group and defeated Sultangazispor, the champions of Group 11, in the promotion play-offs. They secured a 2–0 victory in Eskişehir on 24 April 2016, with goals from Sinan Pektemek and Hamza Mutlu, returning to professional football after two years.
In the 2023–24 season, Kocaelispor finished 6th in the TFF First League, earning a place in the play-off quarter-finals but were eliminated by Çorum. In the 2024–25 season, one day before their away match against Esenler Erokspor, Fatih Karagümrük's 1–0 loss to Boluspor ensured Kocaelispor's promotion by securing 1st place in the league with three weeks remaining. Thus, the club achieved promotion to the Süper Lig after 16 years.
In the upper left corner of the crest, a blue silhouette represents the Gulf of İzmit (İzmit Körfezi), symbolizing the city's connection to the sea. Adjacent to it is a yellow sun, symbolizing energy and hope. On the right side of the crest, three yellow stars are aligned diagonally, typically symbolizing achievements and aspirations of the club. The green and black color scheme has been consistently used by the club since its founding, with green symbolizing nature and vitality, and black representing determination and strength.
What keeps the derby white-hot is less the league table than the combustible mix of geography—barely fifty kilometres separate the Gulf cities—and two ultra cultures, Hodri Meydan and Tatangalar, whose confrontations regularly push the fixture onto Turkey high-risk list. Flash-point moments include the 5–1 match of 8 May 2011 when Kocaelispor’s Gökhan Bozkaya deliberately scored an own goal to avoid a 4–1 scoreline that would have echoed Kocaeli’s “41” licence-plate code, the earthquake-relief friendly of 22 February 2023 that still saw flares and scuffles despite both clubs donating gate receipts to AFAD and the Red Crescent, Kocaelispor’s first away win in Sakarya Province for forty-two years on 10 November 2024, and their 3–1 home victory on 31 March 2025 in front of a full Kocaeli Stadium.
2025–26 | Süper Lig | 14th | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
UEFA Cup Winners' Cup | 4 | 2 | 1 | 1 | 4 | 2 | +2 |
UEFA Cup | 4 | 0 | 1 | 3 | 0 | 7 | –7 |
UEFA Intertoto Cup | 10 | 3 | 3 | 4 | 11 | 14 | –3 |
1993–94 | UEFA Cup | R1 | Sporting CP | 0–0 | 0–2 | 0–2 | |
1996 | UEFA Intertoto Cup | Group 11 | Uralmash | align=center | 0–2 | 4th | |
CSKA Sofia | 1–3 | align=center | |||||
Strasbourg | align=center | 1–1 | |||||
Hibernians | 5–3 | align=center | |||||
1997–98 | Cup Winners' Cup | R1 | Național București | 2–0 | 1–0 | 3–0 | |
R2 | Lokomotiv Moscow | 0–0 | 1–2 | 1–2 | |||
1999 | UEFA Intertoto Cup | R2 | FK Ventspils | 2–0 | 1–1 | 3–1 | |
R3 | MSV Duisburg | 0–3 | 0–0 | 0–3 | |||
2000 | UEFA Intertoto Cup | R1 | FK Atlantas | 0–1 | 1–0 | 1–1, 4–5 (p) | |
2002–03 | UEFA Cup | R1 | Ferencváros | 0–1 | 0–4 | 0–5 |
Recep Durul |
Veli Başkurt |
Ahmet Arık |
Gürhan Darcan |
Fazile Ayşe Özkurt |
Osman Çakır |
Ramazan Daş |
Kadir Genç |
Serkan Akpolat |
Engin Arat |
Ahmet Şahin |
Kamil Sert |
Serkan Bulut |
Mert Kavşut |
Orhan Dönmez |
Zeynel Abidin Akyol |
Serkan Bozbağ |
Rafet Kırgız |
Okan Yıldırım |
Selçuk İnan |
30 Mar 1968 |
1 Feb 1969 |
30 Jun 1971 |
30 Jun 1973 |
30 Jun 1974 |
2 Jan 1976 |
30 Jun 1976 |
30 Jun 1977 |
30 Jun 1977 |
30 May 1978 |
30 Jun 1979 |
30 Jun 1980 |
12 Apr 1982 |
30 Jun 1982 |
19 Oct 1982 |
30 Jun 1983 |
30 Jun 1984 |
28 Oct 1985 |
30 Jun 1986 |
8 Dec 1986 |
26 Apr 1987 |
30 Jun 1987 |
30 Jun 1988 |
30 Jun 1989 |
30 Jun 1991 |
20 Jan 1994 |
30 Jun 1994 |
28 Sep 1996 |
21 Jan 1997 |
30 Jun 1998 |
29 Aug 2000 |
27 Nov 2000 |
8 Oct 2002 |
30 Jun 2003 |
21 Nov 2003 |
26 Mar 2004 |
12 Oct 2004 |
30 Jun 2005 |
4 Oct 2005 |
7 Mar 2006 |
22 Jun 2006 |
27 Oct 2006 |
9 Feb 2007 |
30 Jun 2007 |
28 Oct 2007 |
23 Apr 2008 |
25 Sep 2008 |
22 Jan 2009 |
30 Jun 2009 |
5 Feb 2010 |
16 Feb 2010 |
22 Apr 2010 |
22 Apr 2011 |
11 Oct 2011 |
2 Dec 2011 |
30 Jun 2012 |
30 Jun 2013 |
19 Apr 2013 |
3 Oct 2013 |
30 Jun 2014 |
30 Jun 2015 |
18 Jun 2016 |
18 Sep 2017 |
11 Dec 2017 |
30 Jun 2019 |
22 Oct 2019 |
23 Sep 2020 |
15 Jan 2021 |
24 Jan 2022 |
11 Apr 2022 |
30 May 2023 |
19 Feb 2024 |
12 May 2024 |
20 Dec 2024 |
30 Jun 2025 |
present |
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