Area code (813) is in the state of FL. Below, are the major cities in the area code (813). Area Codes Starting with 8 Area Code (801) Area Code (802) Area Code (803) Area Code (804) Area Code (805) Area Code (806) Area Code (808) Area Code (810) Area Code (812) Area Code (814) Major Cities in 813 TAMPA, FL (2,625,826) BRANDON, FL (498,902)