310 vs 424
West LA & South Bay · West LA / South Bay (overlay)
They're related. All-services overlay covering the same area as 310; California's first area-code overlay. New 424 numbers became assignable August 26, 2006 (mandatory 10-digit dialing began July 26, 2006).
310
West LA & South Bay
Region
Western and southern Los Angeles County (Westside, South Bay, Harbor) and Santa Catalina Island, California
Type
geographic
In service since
1991
Overlay status
Active — 424 all-services overlay of the 310 geographic area, effective July 26, 2006 (California's first overlay).
424
West LA / South Bay (overlay)
Region
West Los Angeles, the Westside, the South Bay and L.A. County beach cities (shares 310's geography)
Type
geographic
In service since
2006
Overlay status
Active — 424 is itself the overlay code layered on 310 (in service since August 26, 2006).
How to read this. We compare only facts that have a source — place, history, and relationship. We deliberately do not score which area code is “better,” “more valuable,” or “more trustworthy”; those are not properties of an area code.
Other comparisons
Facts and dates are cited on each area code's profile (310 · 424); status and in-service data via NumberResearch. How this is made.