North American Numbers Source-cited · ownership disclosed
Area code
510
In service
United States · since 1991

Oakland

Area code 510 serves much of the East Bay, including Oakland and Berkeley, in parts of Alameda and Contra Costa Counties. It was split from 415 in 1991 and is overlaid by area code 341.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Oakland
Type
geographic
Status
in service
In service since
1991
Projected exhaust
2073 Q4

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 510 is

Western Alameda County and western Contra Costa County (East Bay)..

Communities served wholly or partly by 510:

OaklandBerkeleyFremontHaywardRichmondSan LeandroAlameda

Representative list; many additional East Bay communities are served.

B · Relationships

How it relates to other codes

The codes 510 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?

Split from · 1991 415 San Francisco Split from 415 on September 2, 1991.
Overlay · 2019 341 Oakland (overlay) All-services overlay of 510; new codes available July 22, 2019.
Spawned · 1998 925 Concord / Walnut Creek Inland East Bay split off from 510 on March 14, 1998.
What's changing. Overlaid by 341; mandatory ten-digit dialing.
C · History

How 510 got here

1991-09-02
Area code 510 established via split from area code 415.
Source: Wikipedia
1998-03-14
Area code 925 split from 510 for the inland East Bay.
Source: Wikipedia
2019-06-22
Ten-digit dialing became mandatory.
Source: Wikipedia
2019-07-22
New central office codes in 341 (overlay) became available.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
800
Prefixes available
0
Thousands-blocks assigned
3,276

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 510 with another code →
Sources
Wikipedia ↗
Area codes 510 and 341
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (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.