| Amazing Grace General Contractors INC | Franklin Estuardo Villatoro | — | (925) 338 6717 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Amb Electric | Mendoza Abrahan | billbaraona@gmail.com | (925) 325 5929 | Electricians | Concord · Contra Costa County | — | — |
| Amber Electric | Christopher John Davis | anapbm@gmail.com | (510) 725 8893 | Electricians | Richmond · Contra Costa County | — | — |
| Amber Electrical Service | Sarajzadeh Fariborz | hello@rfuenzalida.com | (925) 483 6108 | Electricians | Martinez · Contra Costa County | — | — |
| Ambient Air INC | Robert Evans Wallace | — | (925) 634 8859 | HVAC | Discovery Bay · Contra Costa County | — | — |
| Amc Construction | Aaron Michael Carvajal | agustinamingote@gmail.com | (925) 360 2444 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Ame Builds | Ame Builds | — | (510) 385 0730 | GC, remodel, ADU | Moraga · Contra Costa County | — | — |
| Amed S Omari | Amed S Omari | — | (925) 695 4001 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Amer Construction INC | Firas Abddulwadoud Jandali | — | (510) 367 4548 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| America Hauling | America Hauling | — | (510) 815 2092 | Other | El Sobrante · Contra Costa County | — | — |
| American Air Conditioning Company | Obinyan Anthony | — | (510) 417 2955 | HVAC | Pinole · Contra Costa County | — | — |
| American Alarm Co INC | David Alan Miller | — | (925) 779 1121 | Electricians | Antioch · Contra Costa County | — | — |
| American Building Group INC | John Michael Pluff | — | (925) 452 8239 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| American Concrete Cutting And Breaking INC | Lawrence Scott Israel | — | (925) 394 6600 | Other | Concord · Contra Costa County | — | — |
| American Construction | Sauvain Steven | — | (707) 315 0945 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| American Eagle Engineering | Armando Calmo Perez | — | (510) 253 8049 | Other | El Sobrante · Contra Costa County | — | — |
| American Elite Professional Services Group INC | Don Wayne Bartelmie | — | (925) 303 8197 | Electricians | Antioch · Contra Costa County | — | — |
| American Flagpole Company | Steven Eugene Owens | — | (925) 577 8857 | Other | Byron · Contra Costa County | — | — |
| American Floors | American Floors | — | (925) 360 3792 | Other | Concord · Contra Costa County | — | — |
| American Glazing & Aluminum | Lisa Rae Garner | — | (925) 522 1125 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| American Grout Specialists | Zachary Edward Levy | — | (415) 720 3288 | Other | Danville · Contra Costa County | — | — |
| American Home Improvement | American Home Improvement | — | (925) 548 0511 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| American Home Painting | American Home Painting | — | (925) 768 5531 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| American Home Upgrades-hvac Utor Services | Diego Alfonso Utor Aliaga | — | (415) 350 4286 | HVAC | Brentwood · Contra Costa County | — | — |
| American Housing INC | Dinesh Sawhney | foundingfather1776@usa.com | (510) 593 9111 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| American Industrial Scaffolding INC | Jose Alfredo Flores | — | (925) 849 4885 | Other | Concord · Contra Costa County | — | — |
| American Kitchen Company INC | Aguilar Hildebrand Aguilar | — | (866) 346 8633 | GC, remodel, ADU | Bay Point · Contra Costa County | — | — |
| American Mantels And Construction Company | David Keith Cloonan | — | (925) 934 7106 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| American Mechanical; Iq Controls | Kyle Sarvous Blocker | — | (925) 946 9101 | HVAC | Walnut Creek · Contra Costa County | — | — |
| American Millwright Services | Joe Casey Lawrence | — | (510) 421 9997 | Other | Antioch · Contra Costa County | — | — |
| American Pacific Construction | Ronald Jay Henson | — | (925) 989 2864 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| American Painting | American Painting | — | (510) 525 7220 | Windows, patio, painters | Pinole · Contra Costa County | — | — |
| American Pipe Bursting LLC | Austin Phillip Barber | — | (925) 586 7970 | Other | Martinez · Contra Costa County | — | — |
| American Power Delivery | Robert Jr Gonzalez | — | (925) 439 7000 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| American Property Management | American Property Management | — | (925) 831-8900 | Property managers | San Ramon · Contra Costa County | — | — |
| American Refrigerant Services INC | Michael Dennis Amell | — | (925) 766 6982 | HVAC | Concord · Contra Costa County | — | — |
| American Refrigeration | American Refrigeration | — | (925) 705 3800 | HVAC | Pinole · Contra Costa County | — | — |
| American Roofing And Home Improvement | Panfilo Garcia Armas | — | (415) 575 0916 | Other roofers | Richmond · Contra Costa County | — | — |
| American Underground Contractor | Doyle Edward Jr Swafford | — | (925) 634 0554 | Other | Byron · Contra Costa County | — | — |
| Americana Plumbing Solutions INC | Eduardo Alvarado | — | (925) 222 7678 | Other | Antioch · Contra Costa County | — | — |