Area code 310 serves the Westside and South Bay of Los Angeles County, California, plus Santa Catalina Island.
The essentialsNumbering data from NumberResearch · as of 2026-09-17
Place
West LA & South Bay
Type
geographic
Status
in service
In service since
1991
Country
United States
Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records), as of 2026-09-17. Assignment records show initial assignees, not the carrier serving a number today.
Where 310 is
Western and southern Los Angeles County (Westside, South Bay, Harbor) and Santa Catalina Island, California.
Communities served wholly or partly by 310:
Santa MonicaBeverly HillsMalibuManhattan BeachTorranceInglewoodEl SegundoRedondo BeachSan PedroSanta Catalina Island
Representative 310 communities from secondary sources; exact per-city assignment was not verified against a CPUC/NANPA rate-center list.
How it relates to other codes
The codes 310 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?
Overlay · 2006424West LA / South Bay (overlay)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).
Split from · 1991213Downtown & Central LA310 was created by a geographic split from 213 on November 2, 1991.
Spawned · 1997562562 split off from 310 on January 25, 1997 for southeastern LA County and part of Orange County.
History
1991-11-02
Area code 310 put into service, split from 213.
Source: Wikipedia (secondary)
1997-01-25
Area code 562 split from 310 for southeastern LA County / part of Orange County.
Source: Wikipedia (secondary)
2006-07-26
Mandatory 1+10-digit dialing began across the 310/424 region; new 424 numbers became assignable a month later, August 26, 2006.
Source: CPUC news release 58447 (primary)
What's changing. Active — 424 all-services overlay of the 310 geographic area, effective July 26, 2006 (California's first overlay).
How full it is
Prefixes assigned
800
Prefixes available
0
Projected exhaust
2043 Q1
Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-17 (CC BY 4.0).
Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.