Area codes 310 and 424

Area code 310 is a California telephone area code that was split from area code 213 on November 2, 1991. Area code 424 is an overlay of 310 that became effective on July 26, 2006. It is the area code that covers the West Los Angeles and South Bay areas of Los Angeles County, including Santa Catalina Island (located 26 miles (42 km) south of the mainland portion of Los Angeles County). It also includes a small portion of Ventura County. Area code 424 is the first non-mobile area code overlay in Southern California. Therefore, callers in the 310 area code are no longer able to dial a seven-digit number even if they are dialing within the same area code. Until the overlay of area codes 657 and 714 became active in 2008, the 310-424 complex was the only area code overlay in the entire state of California, despite California having more area codes than any other state.

On January 25, 1997 area code 310 was split, creating area code 562 for the southeast portion of Los Angeles County and a portion of Orange County.

Area code 562 was originally destined to be an overlay code for cellular telephones and pagers for the existing 310 area, to go into service in late 1995, to be extended to overlay the 213 and 818 areas the following year. However, the plans were changed to a simple split of 310, as the California Public Utilities Commission decided that overlay would have disadvantaged customers of smaller companies in requiring 10 digit dialling.

The south and east portions of 310, roughly the Gateway Cities area of Los Angeles County from Long Beach to Whittier and parts of Orange County became area code 562 on January 25, 1997.

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