Located in the Central (GMT -06:00) time zone. Area code 708 serves the state of Illinois. This area code was assigned on April 4th, 1988. On November 11th, 1989 it went into service. 708 is a General Purpose Code. 708 service area does overlap with 464 area codes. Dialing pattern for local calls within the same NPA (area code) is 7D.