| Copala Floors LLC | Alexis Ezequiel Rosas | alexisrosas@copalafloors.com | (510) 478 8319 | Other | Castro Valley · Alameda County | — | — |
| Copeland Mechanical INC | Miled Simon Tanios | copelandmechanical@sbcglobal.net | (510) 795 7216 | HVAC | Newark · Alameda County | — | — |
| Corban Construction | Corban Soon Lee | — | (925) 255 5015 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Corban Floor Coverings INC | David Neil Jr Couch | — | (510) 979 9059 | Other | Hayward · Alameda County | — | — |
| Corbin Construction | William Lee Corbett | info@corbin-construction.com | (925) 570 4704 | GC, remodel, ADU | San Lorenzo · Alameda County | — | — |
| Coreframe Builders | Coreframe Builders | brilliant@coreframebuilders.com | (415) 909 9501 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Cornelious Painting | Cornelious Painting | — | (810) 925 7272 | Windows, patio, painters | West Oakland · Alameda County | — | — |
| Cornelis Van Leeuwen | Cornelis Van Leeuwen | — | (510) 667 2569 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Cornerstone Select Builders INC | Lisa Marie Freels | — | (925) 495 4333 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Corona Molding | Corona Molding | — | (408) 823 2120 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Coronado Construction | Juan Antonio Coronado Trujillo | impallari@gmail.com | (510) 593 5211 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Corporate Community Development | Corporate Community Development | — | (949) 456 5022 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Corporate Interior Solutions | Jesus Martin Silva | — | (510) 670 8800 | Other | Hayward · Alameda County | — | — |
| Corral Construction Co | Jorge Diaz Corral | info@corral-construction.com | (510) 351 2500 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| Corral Coolng And Heating | Corral Coolng And Heating | — | (510) 951 5852 | HVAC | Alameda · Alameda County | — | — |
| Corral Custom Cabinetry | Corral Custom Cabinetry | — | (510) 670 0848 | Other | Hayward · Alameda County | — | — |
| Correia Tile & Granite | Correia Tile & Granite | — | (510) 975 0725 | Other | Hayward · Alameda County | — | — |
| Cory C Smith DBA Richco Floors | Richco Floors | — | (209) 858 8633 | Other | Pleasanton · Alameda County | — | — |
| Cost U Less Plumbing And Drain | Juarez-lopez Pablo | — | (510) 866 1099 | Other | San Leandro · Alameda County | — | — |
| Costa Matt Construction | Matthew Joseph Costa | — | (718) 290 5758 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Costel General Electric | Paduraru Costica | — | (510) 910 5622 | Electricians | San Leandro · Alameda County | — | — |
| Costello's Plumbing | Costello's Plumbing | — | (510) 415 0725 | Other | San Leandro · Alameda County | — | — |
| Cota Electric INC | Edgar Cota | — | (510) 935 5000 | Electricians | Castro Valley · Alameda County | — | — |
| Counter Pros INC | Jorge Paolo Alvarado Reyes | — | (213) 219 9426 | Other | Fremont · Alameda County | — | — |
| Counter Solutions | Counter Solutions | — | (925) 455 1995 | Other | Livermore · Alameda County | — | — |
| Counterforce INC | James Edmund Ferguson | — | (510) 835 5400 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Country Builders Construction INC | Kelly Lewis Offill | — | (925) 373 1020 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| County Power Sweep | County Power Sweep | — | (510) 378 3391 | Other | Fremont · Alameda County | — | — |
| Covarrubias Tile | Covarrubias Tile | — | (925) 658 8453 | Other | San Lorenzo · Alameda County | — | — |
| Covert Water Heaters INC | Correa Victor Monroy | — | (510) 755 8320 | Other | Hayward · Alameda County | — | — |
| Cowles Construction | Bruce Harder Jr Cowles | — | (415) 290 9060 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Cowles Construction Corp | Bruce Harder Jr Cowles | — | (415) 290 9060 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Cox Roofing INC | Jorge Vinicio Cox Perez | ndevon@coxroofing.com | (510) 467 4942 | Other roofers | Oakland · Alameda County | — | — |
| Coyle Residential INC | Patrick Michael Coyle | — | (510) 376 3887 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Coyote Power Electric | Ledezma Cienfuegos Rafael | coyotepowerelectric@hotmail.com | (510) 862 2274 | Electricians | Hayward · Alameda County | — | — |
| Cp Landscaping | Cp Landscaping | — | (510) 798 4152 | Windows, patio, painters | San Leandro · Alameda County | — | — |
| Craft Engineering | Luis Alfredo Almaraz Rosales | info@craft-engineering.com | (415) 286 8486 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Craig Allen Smith | Craig Allen Smith | — | (510) 673 2614 | Other | Fremont · Alameda County | — | — |
| Craig Bordi | Craig Bordi | — | (510) 418 2527 | Other | San Leandro · Alameda County | — | — |
| Craig Matoza Construction | Craig David Matoza | — | (510) 701 9771 | GC, remodel, ADU | San Leandro · Alameda County | — | — |