On 8 January 2015, in front of 20,152 spectators, Kocaelispor set a record for the highest attendance at a Turkish Regional Amateur League encounter.

[1] Prior to establishment of Kocaelispor, the executive board representatives of Baçspor, a local football club, had demanded a new plat from İzmit Municipality to assure a place for training the sports in 1957.

Osman Gencal, city mayor at the time, had been interested in finding a place for training due to his sportive background as a former sportsman and a member of Baçspor.

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.

Beating Kayserispor with a 7–2 final score in 1st match day, collecting 25 points in first 10 weeks, Kocaelispor ended the first half of the fixture as the league leader.

Stevica Kuzmanovski and Mirko Mirković (latterly gained Turkish citizenship with name Mert Meriç) are other Yugoslav players in defence position.

Bülent Baturman, Halil İbrahim Kara, Melih Erdem, Ergun Kula are some of other notable players at that squad.

However, this return lasted one season due to money shortage and relegated again to First League after lost 3–1 home match against Trabzonspor on 9 May 2009, at Round 31 as finishing 17th.

Kocaelispor relegated to TFF Second League, third tier of Turkish football once after 2–1 losing away match against Kartalspor on 4 April 2010.

[5] They defeated them as 2–0 with Sinan Pektemek and Hamza Mutlu's goals on 24 April 2016 in Eskişehir and returned professional level after 2 years.

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