 He finished his career with Iznikspor in 2011–12, the same team he started his career with in 1994.Hasan Sönmez spent his youth career with Iznikspor, he made his career debut on 17 September 1994 in a 2–1 away defeat against Beylerbeyi.He made 23 appearances in the 1994–95 TFF Third League season for Iznikspor before departing in 1995 to sign his first professional contract with Gençlerbirliği.