Area Code Overview

Area code 510 is a geographic telephone area code in California that went into service on September 2, 1991. The geographic regions covered by this area code overlay has a population of approximately 1,906,674.

Overlay and Dialing Rules

Area Code: 510
State: California
Type: General Purpose Code
In Service Date: September 2, 1991
Overlay Complex: 341/510
Local Dialing Plan: This area requires you to dial 1 and the area code when calling locally.

Estimated Number of Assigned Phone Numbers in Area Code 510

This area code is ranked 86th out of 363 nationwide in estimated assigned phone numbers. Within the state territory it serves, it is ranked 16th out of 39.

6,243,000

Estimated Service-Type Mix of Assigned Phone Numbers in Area Code 510

Total assigned 6,243,000

Wireless

2,480,000 assigned

39.72%

Wireline and VoIP

3,429,000 assigned

54.93%

Other / Unclassified

334,000 assigned

5.35%

Estimated Share of Wireless Numbers Originally Assigned to Each Carrier in Area Code 510

Estimated assigned wireless phone numbers: 2,480,000

Numbers may later be ported to another carrier, but this chart reflects original number assignment, not current subscriber share.

T-Mobile 1,110,000 (44.76%)

AT&T Wireless 816,000 (32.90%)

Verizon Wireless 520,000 (20.97%)

33 WIRELESS INC. 30,000 (1.21%)

SEQUOIA WIRELESS, LLC 4,000 (0.16%)

Estimated Share of Wireline and VoIP Numbers Originally Assigned to Each Carrier in Area Code 510

Estimated assigned wireline and VoIP phone numbers: 3,429,000

AT&T 1,674,000 (48.82%)

Onvoy 536,000 (15.63%)

Bandwidth 420,000 (12.25%)

Lumen 218,000 (6.36%)

Comcast Business 112,000 (3.27%)

UTILITY TELECOM GROUP, LLC - CA 93,000 (2.71%)

MCIMETRO ACCESS TRANSMISSION SERVICES LLC 88,000 (2.57%)

Peerless Network 87,000 (2.54%)

Spectrum 68,000 (1.98%)

SONIC TELECOM, LLC - CA 37,000 (1.08%)

PAETEC ITEL, LLC 20,000 (0.58%)

Telnyx 20,000 (0.58%)

Other / Unclassified Assigned Numbering in Area Code 510

Estimated assigned other or unclassified phone numbers: 334,000

SPOK, INC. 110,000 (32.93%)

U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 66,000 (19.76%)

AMERICAN MESSAGING SERVICES, LLC 40,000 (11.98%)

TELEPORT COMMUNICATIONS AMERICA, LLC - CA 40,000 (11.98%)

IP HORIZON LLC 28,000 (8.38%)

NORTH COUNTY COMMUNICATION CORPORATION - CA 20,000 (5.99%)

SHELCOMM 10,000 (2.99%)

INTEGRATED PATH COMMUNICATIONS, LLC - CA 9,000 (2.69%)

WHITESKY COMMUNICATIONS, LLC 5,000 (1.50%)

HD CARRIER LLC 4,000 (1.20%)

AIRESPRING, INC. 1,000 (0.30%)

FRACTEL, LLC 1,000 (0.30%)

Cities and Towns in Area Code 510

Crockett, California Fremont, California Hayward, California Hercules, California Oakland, California Pinole, California Richmond, California

These geographic regions are also served by area code 341.

How These Figures Were Built

These figures are estimates based on public phone-number assignment records. They are meant to show the likely mix of assigned phone numbers associated with area code 510, not live customer counts.

Some providers may have assigned phone numbers tied to this area code even if they do not actively market or sell service locally. These figures reflect public number-assignment records, not confirmed local service availability.

They also do not reflect number portability at the individual phone-number level, so some numbers may now be used on a different network or by a different provider than the original assignment records suggest.

Population data and locality matching provided by GeoNames.

Last refreshed: April 15, 2026 6:22 pm