| Sciens Sabah Division | Terry John Heath | — | (925) 734 5750 | Electricians | Pleasanton · Alameda County | — | — |
| Scot Winkler | Scot Winkler | — | (925) 360 0972 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Scott Haile INC DBA California Landscapes | Scott Douglas Haile | — | (800) 462 3475 | Windows, patio, painters | Pleasanton · Alameda County | — | — |
| Scott Lutz | Scott Lutz | — | (925) 321 1768 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Scott R Banister | Scott R Banister | — | (510) 684 4563 | Electricians | Berkeley · Alameda County | — | — |
| Scpro Painting | Scpro Painting | — | (510) 479 5438 | Windows, patio, painters | Oakland · Alameda County | — | — |
| Scroggins Construction A Partnership | Dale Ray Scroggins | — | (510) 657 2592 | GC, remodel, ADU | Sunol · Alameda County | — | — |
| Sd Adams Corp | Samuel Demond Adams | — | (410) 804 5766 | Other | Alameda · Alameda County | — | — |
| Sdac Lining Group LLC | Samuel Demond Adams | — | (415) 963 1153 | Other | Alameda · Alameda County | — | — |
| Seal Home Remodeling | Hieu Chi Khuu | pham@sealhomeremodeling.com | (510) 435 3535 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Seal Well INC DBA Renaissance Stone Care & Waterproofing | Chevan Denham Goonetilleke | — | (408) 998 4700 | Windows, patio, painters | Castro Valley · Alameda County | — | — |
| Seamus Vanecko | Seamus Vanecko | sv@bcsincsolutions.com | (415) 821 1861 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Sean Chau Construction Roofing | Chau Sean | — | (415) 858 2213 | Other roofers | Oakland · Alameda County | — | — |
| Sean Puckett | Sean Puckett | — | (510) 677 4724 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Seaside Refrigeration | Seaside Refrigeration | — | (510) 379 6138 | HVAC | Oakland · Alameda County | — | — |
| Seasun Construction | Hoi Sung Wong | — | (510) 289 6237 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| Segale Bros Wood Products | Segale Bros Wood Products | — | (510) 300 1170 | Other | Hayward · Alameda County | — | — |
| Segale Bros Wood Products INC | Daniel Aric Segale | — | (510) 300 1170 | Other | Hayward · Alameda County | — | — |
| Segelke Bros Carpets | Segelke Bros Carpets | — | (510) 862 1820 | Other | San Leandro · Alameda County | — | — |
| Seifert Engineering INC | Wendell Peter Seifert | — | (510) 844 4540 | Electricians | Oakland · Alameda County | — | — |
| Select Mechanical INC | Scott Thomas Owens | — | (925) 447 1500 | HVAC | Livermore · Alameda County | — | — |
| Select Pavers INC | Luiz Fernando Braga Cardoso | — | (510) 397 0908 | Other | Union City · Alameda County | — | — |
| Select Windows & Doors & More | Larry Keith Leonard | — | (925) 918 2440 | GC, remodel, ADU | Dublin · Alameda County | — | — |
| Seller Center INC | Wai Ting Siu | interested@domainmarket.com | (510) 387 7828 | GC, remodel, ADU | Emeryville · Alameda County | — | — |
| Semolina Design INC | Gabriel Kennedy Beil | info@semolinadesign.com | (510) 917 5090 | Other | Oakland · Alameda County | — | — |
| Semper Solaris | Semper Solaris | — | (888) 210-3366 | EV chargers | Alameda · Alameda County | — | — |
| Senhsiung Chen | Senhsiung Chen | — | (341) 314 8497 | Electricians | Union City · Alameda County | — | — |
| Sentinel Fire Protection INC | Mark Anthony Blanchietti | — | (510) 259 1500 | Other | Hayward · Alameda County | — | — |
| Sepulveda Welding | Sepulveda Welding | — | (760) 217 1678 | Other | San Leandro · Alameda County | — | — |
| Sequeira Plumbing | Sequeira Plumbing | — | (510) 483 3620 | Other | San Leandro · Alameda County | — | — |
| Sequoia Fire Protection | Cesar Vidal Garcia | eduardo.garcia@sequoiafireprotection.com | (510) 882 9175 | Other | Oakland · Alameda County | — | — |
| Serendipity Pools LLC | Lawrence William Saari | — | (925) 525 8015 | Pool | Livermore · Alameda County | — | — |
| Sergent Revital-construction & Development | Joseph Darin Sergent | — | (859) 333 9549 | GC, remodel, ADU | San Lorenzo · Alameda County | — | — |
| Sergio Lopez Roofing | Sergio Lopez Rodriguez | — | (510) 774 3382 | Other roofers | San Leandro · Alameda County | — | — |
| Sergio's Painting | Sergio's Painting | — | (510) 352 1149 | Windows, patio, painters | San Leandro · Alameda County | — | — |
| Serpico | Peter Novak | — | (510) 293 0341 | Windows, patio, painters | Hayward · Alameda County | — | — |
| Serrano Kitchen And Bath | Serrano Kitchen And Bath | — | (925) 580 1766 | GC, remodel, ADU | Pleasanton · Alameda County | — | — |
| Serrano Siding | Serrano Siding | — | (510) 357 5782 | Windows, patio, painters | Fremont · Alameda County | — | — |
| Serranos Roofing LLC | Nestor Jacobo Serrano | — | (510) 890 5880 | Other roofers | Oakland · Alameda County | — | — |
| Service # 1 Plumbing INC | Victor Hugo Resendiz Pulido | — | (510) 258 4498 | Other | Hayward · Alameda County | — | — |