| Allied Landscape | Loren Emmett Mc Irvin | — | (925) 280 0161 | Windows, patio, painters | Livermore · Alameda County | — | — |
| Alligator Plumbing INC | Jason Benton Debonis | — | (925) 575 7584 | Other | Castro Valley · Alameda County | — | — |
| Allmodular Systems INC | Osorio Vicente Contreras | receiving@allmodularsystems.com | (510) 887 9000 | Other | Hayward · Alameda County | — | — |
| Allpro Construction | Hodzic Nermin | — | (650) 303 2628 | GC, remodel, ADU | Castro Valley · Alameda County | — | — |
| Allstate Plumbing Co | Paul Revere Reeder | — | (510) 656 6504 | Other | Fremont · Alameda County | — | — |
| Ally Builder LLC | Jinghua Wang | — | (510) 353 3677 | GC, remodel, ADU | Union City · Alameda County | — | — |
| Almavana Construction | Rizo Benjamin | — | (510) 427 5655 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Alo Construction | Timothy James Alo | — | (510) 797 8830 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Alonzo & Sevilla Flooring Corp | Christiam Johan Alonzo Cruz | — | (323) 738 3254 | Other | Hayward · Alameda County | — | — |
| Alpen Electric INC | Erich John Turk | — | (510) 569 0942 | Electricians | San Leandro · Alameda County | — | — |
| Alpes Cooling & Heating | Alpes Cooling & Heating | — | (650) 921 7609 | HVAC | Hayward · Alameda County | — | — |
| Alpha Design & Construction | Pham Anthony | — | (510) 520 2609 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Alpha Electric And Construction INC | Phan Thanh Pham | — | (570) 861 6185 | HVAC | Union City · Alameda County | — | — |
| Alpha One Roofing INC | Arellano Jaime | — | (510) 904 2024 | Other roofers | San Leandro · Alameda County | — | — |
| Alpha Plus_nelson General Contractor | Alpha Plus_nelson General Contractor | — | (510) 579 5507 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Alpha-winfield Contractors INC DBA Winfield Construction Company | Kenneth Johnson Winfield | — | (510) 652 4712 | GC, remodel, ADU | Emeryville · Alameda County | — | — |
| Alphabet Roofing Corporation | Muhammad Rustam Zazai | — | (408) 714 9496 | Other roofers | Union City · Alameda County | — | — |
| Alpine Construction & Engineering | Derek Khang-dinh Chau | — | (510) 715 7260 | Other | Oakland · Alameda County | — | — |
| Alpine Mechanical Service Company INC | Scott Daniel Bullis | — | (650) 592 7955 | HVAC | Livermore · Alameda County | — | — |
| Alta Electric Sco | Kho Brian | — | (510) 207 0786 | Electricians | San Leandro · Alameda County | — | — |
| Altamira Construction Company | Daniel Arce Alvarado | — | (510) 304 8535 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Altamont Plumbing INC | Allen Emmanuel King | — | (925) 660 5084 | Other | Livermore · Alameda County | — | — |
| Altamont Water Well And Pump | Altamont Water Well And Pump | — | (925) 980 1066 | Other | Pleasanton · Alameda County | — | — |
| Altek Construction | Padurean Ilie | — | (925) 785 0082 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Alternative Techs Cooperative INC | Roger Hugh Fitzgerald | — | (510) 848 4411 | Other | Berkeley · Alameda County | — | — |
| Altero Construction LLC | Elie Wadih Alchaer | hello@alteroconstruction.com | (510) 325 8494 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Altmann & Associates INC | Jeffrey Berton Altmann | jeffaltmann@gmail.com | (510) 420 8111 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Altura Design & Build | Marco Antonio Barriga Ramirez | — | (209) 662 9532 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Alva Flooring INC | Hernandez Ezequiel Alvarez | — | (925) 550 9826 | Other | Oakland · Alameda County | — | — |
| Alva's Construction INC | Santos Modesto Alva Tello | — | (510) 689 4897 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Alvarado Constructions | Alvarado Constructions | — | (510) 467 3634 | GC, remodel, ADU | Alameda · Alameda County | — | — |
| Alvarez Builders INC | Daniel Alvarez | info@alvarez-builders.com | (650) 885 5398 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Alvarez Construction | Alvarez Sergio | — | (510) 938 8500 | GC, remodel, ADU | Pleasanton · Alameda County | — | — |
| Alvarez Marble Polish & Stone Sealing | Jesus Fernando Alvarez Manzanarez | — | (510) 798 0533 | Other | San Lorenzo · Alameda County | — | — |
| Alvaro's Construction INC | Alvaro Ignacio Picon | — | (510) 719 1518 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Alvin W Electric | Wong Alvin | — | (510) 427 1953 | Electricians | Hayward · Alameda County | — | — |
| Alward Construction Company INC A California Corporation | Mark Mc Rae Oddi | — | (510) 527 6498 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Always Going Plumbing | Always Going Plumbing | — | (510) 314 1472 | Other | Hayward · Alameda County | — | — |
| Am Drywall | Am Drywall | — | (415) 792 2629 | Other | Oakland · Alameda County | — | — |
| Am General Contractor | Dean William Henninger | — | (510) 967 4624 | GC, remodel, ADU | San Leandro · Alameda County | — | — |