Located in the Pacific (GMT -08:00) time zone. Area code 310 serves the state of California. This area code was assigned on August 31st, 1990. On November 2nd, 1991 it went into service. 310 is a General Purpose Code. 310 service area does overlap with 424 area codes. Dialing pattern for local calls within the same NPA (area code) is 1+10D.