| Jahz Concrete Company | Alvarez Hernandez Jose | — | (510) 926 5370 | Other | Oakland · Alameda County | — | — |
| Jaime D Renderos INC DBA Ehret Co Plumbing | Jaquelynn Elizabeth Renderos | — | (510) 528 4292 | HVAC | Oakland · Alameda County | — | — |
| Jake's Landscaping & Tree Services | Luis Oscar Vazquez | — | (650) 520 3107 | Windows, patio, painters | Hayward · Alameda County | — | — |
| Jaki Construction | Earl Curry Williams | — | (510) 880 8780 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| Jaki Demolition Services LLC | Earl Curry Williams | — | (510) 880 8780 | Other | San Leandro · Alameda County | — | — |
| Jakob's Floor Covering | Jakob's Floor Covering | — | (925) 738 8836 | Other | Livermore · Alameda County | — | — |
| Jalcon | John Allan Larson | — | (510) 635 9800 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| James A Inman Construction | James Allan Inman | — | (510) 526 0387 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| James Albert Harper Jr | James Albert Harper Jr | — | (510) 232 6386 | Other | Berkeley · Alameda County | — | — |
| James Construction Services | James Alan Weber | — | (510) 508 5597 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| James D Hague | James D Hague | — | (510) 910 0118 | Other | Oakland · Alameda County | — | — |
| James Island Plastering INC | Irvin George James | — | (510) 568 3671 | Other | Oakland · Alameda County | — | — |
| James J Tarter Builder | James J Tarter Builder | — | (650) 455 1669 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| James Joiner Construction | James Gebhard Joiner | — | (925) 413 6468 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| James L Reeder Jr | James L Reeder Jr | — | (510) 409 7576 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| James Lawrence Leonard | James Lawrence Leonard | — | (559) 960 7358 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| James Mc Carthy Construction | James William Mc Carthy | — | (510) 418 4495 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| James Morales Builder | James Morales Builder | — | (909) 996 3068 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| James Owen Painting & Decorating | James Owen Painting & Decorating | — | (925) 549 0957 | Windows, patio, painters | Dublin · Alameda County | — | — |
| James R Griffin INC | David Craig Martin | — | (510) 792 6515 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| James Tonne Plumbing | James Tonne Plumbing | — | (925) 216 3976 | Other | Livermore · Alameda County | — | — |
| Jami Enterprises | Jami Shahram | — | (818) 223 1124 | GC, remodel, ADU | Emeryville · Alameda County | — | — |
| Jamie Watt's Backhoe Service | Jamie Guy Watt | — | (925) 580 2805 | Other | Livermore · Alameda County | — | — |
| Jannes Design | Jannes Design | — | (415) 488 3474 | GC, remodel, ADU | Emeryville · Alameda County | — | — |
| Jarvis Garage Door INC | Andrew Alan Jarvis | jarvisgaragedoor1@gmail.com | (510) 791 5094 | Other | Fremont · Alameda County | — | — |
| Jason C Longbine | Jason C Longbine | — | (510) 301 5695 | Windows, patio, painters | Oakland · Alameda County | — | — |
| Jason Eggert Construction | Jason Burke Eggert | — | (510) 714 7551 | GC, remodel, ADU | Pleasanton · Alameda County | — | — |
| Jason Ho | Jason Ho | — | (510) 519 1383 | Electricians | San Leandro · Alameda County | — | — |
| Jason Matthew Medeiros | Jason Matthew Medeiros | — | (510) 364 1056 | Other | Fremont · Alameda County | — | — |
| Jason Phong Phung | Jason Phong Phung | — | (510) 316 0283 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Jason Ziganti Construction | Jason Andrew Ziganti | — | (831) 345 6997 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Jasso Plumbing INC | Salinas Sergio Jasso | — | (415) 375 2361 | Other | Oakland · Alameda County | — | — |
| Javier Mendoza | Javier Mendoza | — | (510) 857 4015 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| Javier Valadez | Javier Valadez | — | (510) 565 9608 | Other | San Lorenzo · Alameda County | — | — |
| Jay Construction | Jayaprakash Reddy Lakireddy | info@jayconstruction.com | (510) 715 4024 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Jay Miller Painting | Jay Miller Painting | jay@jaymillerpainting.com | (510) 512 6717 | Windows, patio, painters | Castro Valley · Alameda County | — | — |
| Jay R Smith | Jay R Smith | — | (510) 517 2440 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Jayden Landscaping | Dung Tan Truong | — | (510) 396 7495 | Windows, patio, painters | Hayward · Alameda County | — | — |
| Jazz Heating & Cooling LLC | Frank Nowlan | — | (925) 291 0900 | HVAC | Pleasanton · Alameda County | — | — |
| Jb Construction | Justin Michael Bennett | — | (925) 487 8924 | GC, remodel, ADU | Livermore · Alameda County | — | — |