Area Code Overview

Area code 628 is a geographic telephone area code in California that went into service on March 21, 2015. The geographic regions covered by this area code overlay has a population of approximately 1,083,926.

Overlay and Dialing Rules

Area Code: 628
State: California
Type: General Purpose Code
In Service Date: March 21, 2015
Overlay Complex: 415/628
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 628

This area code is tied for 295th out of 363 nationwide in estimated assigned phone numbers. Within the state territory it serves, it is ranked 32nd out of 39.

1,853,000

Estimated Service-Type Mix of Assigned Phone Numbers in Area Code 628

Total assigned 1,853,000

Wireless

633,000 assigned

34.16%

Wireline and VoIP

947,000 assigned

51.11%

Other / Unclassified

273,000 assigned

14.73%

Estimated Share of Wireless Numbers Originally Assigned to Each Carrier in Area Code 628

Estimated assigned wireless phone numbers: 633,000

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

T-Mobile 314,000 (49.61%)

Verizon Wireless 199,000 (31.44%)

AT&T Wireless 120,000 (18.96%)

Estimated Share of Wireline and VoIP Numbers Originally Assigned to Each Carrier in Area Code 628

Estimated assigned wireline and VoIP phone numbers: 947,000

Onvoy 437,000 (46.15%)

Bandwidth 137,000 (14.47%)

Lumen 73,000 (7.71%)

Spectrum 73,000 (7.71%)

Peerless Network 56,000 (5.91%)

Commio 38,000 (4.01%)

SONIC TELECOM, LLC - CA 31,000 (3.27%)

Telnyx 22,000 (2.32%)

AT&T 19,000 (2.01%)

Vonage 14,000 (1.48%)

Comcast Business 9,000 (0.95%)

PAETEC ITEL, LLC 9,000 (0.95%)

Other / Unclassified Assigned Numbering in Area Code 628

Estimated assigned other or unclassified phone numbers: 273,000

TELEPORT COMMUNICATIONS AMERICA, LLC - CA 155,000 (56.78%)

FRACTEL, LLC 43,000 (15.75%)

IP HORIZON LLC 26,000 (9.52%)

INTEGRATED PATH COMMUNICATIONS, LLC - CA 12,000 (4.40%)

SHELCOMM 10,000 (3.66%)

WHITESKY COMMUNICATIONS, LLC 8,000 (2.93%)

TON80 COMMUNICATIONS, LLC 6,000 (2.20%)

U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 6,000 (2.20%)

HD CARRIER LLC 3,000 (1.10%)

FIVE9, INC. 2,000 (0.73%)

EXIANT COMMUNICATIONS LLC 1,000 (0.37%)

WAVENATION, LLC 1,000 (0.37%)

Cities and Towns in Area Code 628

Belvedere, California Corte Madera, California Ignacio, California Inverness, California Mill Valley, California Nicasio, California Novato, California Point Reyes, California San Francisco, California San Rafael, California Sausalito, California Stinson Beach, California

These geographic regions are also served by area code 415.

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 628, 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