| Swinderman Olson Construction | Jack D Design & Construction Co Olson | — | (510) 577 0770 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Swing Stage Systems INC | Michael Ross Engeldinger | j8m3so@gmail.com | (510) 885 9810 | Other | Hayward · Alameda County | — | — |
| Swingcraft Door INC | Robert Castro | info@swingcraftdoor.com | (510) 789 5158 | Other | Newark · Alameda County | — | — |
| Symons Landscaping | Symons Landscaping | — | (510) 453 6433 | Windows, patio, painters | San Lorenzo · Alameda County | — | — |
| Synerforce Construction | Tsang Tze Yee | — | (415) 795 3234 | GC, remodel, ADU | Union City · Alameda County | — | — |
| Synergy K Builders | Hosik Hwang | — | (510) 427 7322 | GC, remodel, ADU | Union City · Alameda County | — | — |
| Synergy Power | Jason August Piekarczyk | — | (510) 418 5635 | Electricians | Livermore · Alameda County | — | — |
| Synthesis-design Build Restoration | Kamooneh Kasra | — | (510) 981 0415 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Syserco Energy Solutions INC | Derek Paul Eggers | — | (510) 498 1171 | Electricians | Fremont · Alameda County | — | — |
| Syserco INC | Majd N Khleif | — | (510) 498 1171 | Electricians | Fremont · Alameda County | — | — |
| System Works | System Works | — | (510) 282 0710 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Systems & Space INC | Jordan M Jaime | usuario@empresa.com | (925) 426 1955 | Other | Pleasanton · Alameda County | — | — |
| Systems Unlimited Plumbing | Systems Unlimited Plumbing | — | (510) 780 6025 | Other | Livermore · Alameda County | — | — |
| Syufy Builders | George Michael Syufy | — | (650) 591 9800 | GC, remodel, ADU | Castro Valley · Alameda County | — | — |
| T & T Construction | Yunming Tommy Tsai | — | (510) 881 3399 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| T & T Floors INC | Vien Ngoc Tran | — | (510) 536 8333 | Other | Oakland · Alameda County | — | — |
| T & T Landscaping INC | Danny Cuong Nguyen | — | (650) 333 4103 | Windows, patio, painters | Hayward · Alameda County | — | — |
| T 3 INC | Derek Christopher Ludlow | — | (510) 440 0157 | Windows, patio, painters | Fremont · Alameda County | — | — |
| T 3 Mechanical INC | Stephen Anthony Ii Ferreira | — | (408) 638 7613 | HVAC | Livermore · Alameda County | — | — |
| T 4 Company | Patty M Chu | — | (510) 813 7600 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| T A Plumbing | T A Plumbing | — | (209) 470 2120 | Other | Livermore · Alameda County | — | — |
| T A Roberts | T A Roberts | — | (510) 912 2428 | GC, remodel, ADU | Alameda · Alameda County | — | — |
| T A S Construction | Willie Fletcher Arnold | — | (510) 816 2664 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| T C Builder | T C Builder | — | (510) 213 4814 | Electricians | Oakland · Alameda County | — | — |
| T C Builder | T C Builder | — | (510) 506 2503 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| T C Construction Company | Tran Cuong | — | (510) 504 0715 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| T D Construction | Dashravdan Enkhsaruul | — | (510) 332 4621 | Electricians | Alameda · Alameda County | — | — |
| T D Construction Co LLC | Enkhsaruul Dashravdan | — | (510) 332 4621 | Electricians | Alameda · Alameda County | — | — |
| T D Hurray Const | T D Hurray Const | — | (415) 831 8477 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| T D W Construction INC | Edmundo David Alire | — | (925) 455 5259 | Other | Livermore · Alameda County | — | — |
| T E K Electrical Contractor | Keith Allen Wise | — | (510) 470 8735 | Electricians | San Leandro · Alameda County | — | — |
| T G A Construction | Antone George Abuyaghi | — | (415) 806 7779 | GC, remodel, ADU | Alameda · Alameda County | — | — |
| T G C Construction | Antonio De Jesus Pantoja | — | (650) 922 7451 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| T G Construction Company | Glavinic Tean | — | (408) 439 5591 | GC, remodel, ADU | Dublin · Alameda County | — | — |
| T G Plumbing | T G Plumbing | — | (510) 409 6917 | Other | Fremont · Alameda County | — | — |
| T H L Construction & Maintenance Company | Tony Toan Huynh | — | (510) 368 6018 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| T J's Pool Service | Taeatafa Albert Jr Uelese | — | (925) 209 6562 | Pool | Livermore · Alameda County | — | — |
| T K N Builder | T K N Builder | — | (510) 289 3622 | GC, remodel, ADU | San Lorenzo · Alameda County | — | — |
| T M G Construction | Thomas Michael Gavello | — | (510) 589 6914 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| T M I Construction INC | Robert Jerry Brunetti | — | (510) 226 6168 | GC, remodel, ADU | Fremont · Alameda County | — | — |