Ilhan started his career at Geylang International playing for the youth side before getting promoted to the under-21 side in 2019. In 2021, Ilhan was promoted to the senior side where he make his 2021 Singapore Premier League debut against Lion City Sailors on 9 May 2021.[2] Ilhan then scored a brace against Tanjong Pagar United on 1 August 2021 helping his team to a 3–1 win.
Loan to Young Lions
On 24 January 2023, Ilhan moved to Young Lions on loan while serving his compulsory two years National Service. On 25 February 2023, he make his debut for the club in a 3–0 lost against Albirex Niigata (S).