| All Glass Global INC | Thoai Quang Nguyen | — | (925) 803 1331 | Windows, patio, painters | Dublin · Alameda County | — | — |
| All In Electric | Jesse Miguel Gutierrez | — | (510) 935 2549 | Electricians | Hayward · Alameda County | — | — |
| All In One Floors | All In One Floors | — | (650) 248 7191 | Other | Fremont · Alameda County | — | — |
| All New Painting | All New Painting | — | (510) 221 8469 | Windows, patio, painters | Fremont · Alameda County | — | — |
| All On Electric INC | Joel David Dahlheim | info@allonelectric.com | (925) 447 0581 | Electricians | Livermore · Alameda County | — | — |
| All Panthers Plumbing INC | Monroy Monroy Rodolfo | — | (510) 952 9570 | Other | Hayward · Alameda County | — | — |
| All Phase Quality Construction | Huynh Hien | — | (510) 828 2076 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| All Property Tech LLC | Garrett Kim Woon | office@allpropertytech.com | (510) 513 9595 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| All Purpose Painting & Restoration | All Purpose Painting & Restoration | — | (510) 589 4656 | Windows, patio, painters | Fremont · Alameda County | — | — |
| All Season Construction | Lee Jong Ki | interested@domainmarket.com | (510) 502 7757 | GC, remodel, ADU | Alameda · Alameda County | — | — |
| All Seasons Construction | Jeremy Kahalewai Ke | — | (510) 652 2221 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| All Seasons Heating & Air Conditioning | Jones Dean | — | (510) 917 3016 | HVAC | Oakland · Alameda County | — | — |
| All Seasons Tree Service INC | Suastes Leonel Serrato | — | (650) 924 0121 | Tree | Newark · Alameda County | — | — |
| All Star Team Construction | Lin Wen Biao | — | (510) 418 0700 | GC, remodel, ADU | Castro Valley · Alameda County | — | — |
| All State Builders INC | Frankie Allen Jr Rhodes | — | (209) 569 6261 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| All State Insulation INC | Perez Daniel Espinoza | — | (209) 569 6261 | Other | Fremont · Alameda County | — | — |
| All Weather Roofing | Enrique Jose Barraza | — | (510) 534 1660 | Other roofers | Oakland · Alameda County | — | — |
| All West Fabricators INC | Keith Merritt Lee | — | (510) 657 4900 | Other | Fremont · Alameda County | — | — |
| All-guard Alarm Systems INC | Patricia Ann Cooke | — | (800) 255 4273 | Electricians | Livermore · Alameda County | — | — |
| All-pro Concrete | Alfredo Lawrence Barajas | — | (510) 972 4086 | Other | Hayward · Alameda County | — | — |
| All-weather Construction Company | Gerald Lewis Chastain | — | (510) 693 0755 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| Allcom Electric INC | Charles Michael Neil | — | (510) 656 7099 | Electricians | Pleasanton · Alameda County | — | — |
| Allegro Tile Co | Allegro Giordano | — | (510) 681 7456 | Other | Oakland · Alameda County | — | — |
| Allen Associates | Kim Worthington Allen | enquiries@allen-associates.com | (510) 832 7808 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Allen B Shao | Allen B Shao | — | (510) 557 7622 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Allen Construction Expeditors INC | John Sanford Allen | — | (510) 421 0084 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Allen J Romano General Building Contractor | Allen Joseph Romano | — | (510) 526 8974 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Allen Pfeifer | Allen Pfeifer | — | (510) 589 9856 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Allen Poon Ap Construction & Maintenance | Allen Wah Tim Poon | — | (510) 794 9701 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Allen Steel | Stephanie Louse Beadle | — | (925) 373 7787 | Other | Livermore · Alameda County | — | — |
| Alley Cat Creations | Goldman Niv | — | (510) 277 3303 | Other | San Leandro · Alameda County | — | — |
| Alliance Building Contractors | Paul Junius Jr Evans | — | (650) 402 5350 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Alliance Contracting Services INC | Omar Cuevas Garrido | info@alliancecontractingservices.com | (510) 667 9934 | Other roofers | San Leandro · Alameda County | — | — |
| Alliance Fire INC | Gavin Michael Struk | sales@alliancefire.com | (510) 385 5680 | Other | Oakland · Alameda County | — | — |
| Alliance Glass Company | Kevin Frank Furtado | — | (650) 625 9108 | Windows, patio, painters | Fremont · Alameda County | — | — |
| Allied Construction Enterprises INC | Rafael Concepcion Pascual | — | (510) 520 8723 | GC, remodel, ADU | Dublin · Alameda County | — | — |
| Allied Construction Services | Jason Buck Rittenbach | — | (925) 724 2324 | Other roofers | Livermore · Alameda County | — | — |
| Allied Controls | Allied Controls | — | (510) 706 6750 | Electricians | Hayward · Alameda County | — | — |
| Allied Controls | Mariscal Manuel | — | (510) 317 7722 | Electricians | Castro Valley · Alameda County | — | — |
| Allied Fire Protection | Theodore Robert Vinther | — | (510) 533 5516 | Other | Oakland · Alameda County | — | — |