Area Code Overview

Area code 925 is a geographic telephone area code in California that went into service on March 14, 1998. The geographic regions covered by this area code overlay has a population of approximately 1,449,501.

Overlay and Dialing Rules

Area Code: 925
State: California
Type: General Purpose Code
In Service Date: March 14, 1998
Overlay Complex: 925
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 925

This area code is ranked 182nd out of 363 nationwide in estimated assigned phone numbers. Within the state territory it serves, it is ranked 25th out of 39.

4,948,000

Estimated Service-Type Mix of Assigned Phone Numbers in Area Code 925

Total assigned 4,948,000

Wireless

1,733,000 assigned

35.02%

Wireline and VoIP

2,919,000 assigned

58.99%

Other / Unclassified

296,000 assigned

5.98%

Estimated Share of Wireless Numbers Originally Assigned to Each Carrier in Area Code 925

Estimated assigned wireless phone numbers: 1,733,000

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

T-Mobile 653,000 (37.68%)

AT&T Wireless 617,000 (35.60%)

Verizon Wireless 453,000 (26.14%)

33 WIRELESS INC. 10,000 (0.58%)

Estimated Share of Wireline and VoIP Numbers Originally Assigned to Each Carrier in Area Code 925

Estimated assigned wireline and VoIP phone numbers: 2,919,000

AT&T 1,355,000 (46.42%)

Onvoy 498,000 (17.06%)

Bandwidth 244,000 (8.36%)

Lumen 203,000 (6.95%)

Comcast Business 122,000 (4.18%)

Peerless Network 81,000 (2.77%)

MCIMETRO ACCESS TRANSMISSION SERVICES LLC 79,000 (2.71%)

Spectrum 79,000 (2.71%)

MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 50,000 (1.71%)

UTILITY TELECOM GROUP, LLC - CA 46,000 (1.58%)

Commio 41,000 (1.40%)

TERRA NOVA TELECOM INC. 33,000 (1.13%)

Other / Unclassified Assigned Numbering in Area Code 925

Estimated assigned other or unclassified phone numbers: 296,000

AMERICAN MESSAGING SERVICES, LLC 50,000 (16.89%)

SPOK, INC. 50,000 (16.89%)

TELEPORT COMMUNICATIONS AMERICA, LLC - CA 40,000 (13.51%)

NORTH COUNTY COMMUNICATION CORPORATION - CA 30,000 (10.14%)

IP HORIZON LLC 26,000 (8.78%)

U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 19,000 (6.42%)

FRACTEL, LLC 18,000 (6.08%)

HD CARRIER LLC 18,000 (6.08%)

WHITESKY COMMUNICATIONS, LLC 16,000 (5.41%)

INTEGRATED PATH COMMUNICATIONS, LLC - CA 12,000 (4.05%)

SHELCOMM 10,000 (3.38%)

TON80 COMMUNICATIONS, LLC 5,000 (1.69%)

Cities and Towns in Area Code 925

Antioch, California Clayton, California Concord, California Danville, California Dublin, California East Contra Costa, California Lafayette, California Livermore, California Martinez, California Moraga, California Orinda, California Pittsburg, California Pleasanton, California San Ramon, California Sunol, California Walnut Creek, California

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 925, 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