| Solo Tile & Stone INC | David Ivan Solis | — | (510) 397 6670 | Other | Hayward · Alameda County | — | — |
| Solorzano Landscape Construction | Arturo Munoz Solorzano | — | (510) 415 2208 | Windows, patio, painters | Hayward · Alameda County | — | — |
| Solorzanos INC | Arturo Munoz Solorzano | — | (510) 415 2208 | Windows, patio, painters | Hayward · Alameda County | — | — |
| Solstice Construction | Geoffrey Stewart Roller | — | (415) 205 5797 | Electricians | Oakland · Alameda County | — | — |
| Soltmen Builders | Soltmen Builders | — | (510) 938 2219 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Solvex Building And Design INC | Jeffrey Douglas Shaddock | — | (415) 305 1356 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Sonrise Enterprises INC | Kevin Daniel Copp | — | (510) 305 9061 | GC, remodel, ADU | Dublin · Alameda County | — | — |
| Sonrise Roofing | Adeline Lori Farrer | sonriseroofing58@gmail.com | (510) 791 6457 | Other roofers | Fremont · Alameda County | — | — |
| Sontag Construction INC | Peter William Sontag | bids@sontagconstruction.com | (510) 665 4500 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Sop Construction | Timothy Paul Fehr | — | (319) 318 2202 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Sophos Fire Systems LLC | Christopher David Wilson | cwilson@sophosfiresystems.com | (925) 351 4270 | Electricians | Livermore · Alameda County | — | — |
| Sos Restoration Of East Bay | Sos Restoration Of East Bay | — | (341) 220-0032 | Restoration | Oakland · Alameda County | — | — |
| Sosa Designs Tile & Marble INC | Sosa Jose Martinez | sosadesigns@yahoo.com | (510) 881 6224 | Other | San Leandro · Alameda County | — | — |
| Sosa Kitchen & Bath Remodeling | Sosa Mario | — | (925) 373 7675 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Soto Bay Construction | Soto Soriano Jesus | — | (510) 798 7875 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Souki Construction | Souki Nasig | — | (510) 388 8832 | GC, remodel, ADU | Albany · Alameda County | — | — |
| Sound & Signal INC | Steven Boyd Ackermann | — | (925) 455 1778 | Electricians | Livermore · Alameda County | — | — |
| Soundwise A V & Automation | Rozel Tupaz | — | (925) 202 9304 | Other | Pleasanton · Alameda County | — | — |
| Source Energy LLC | Theodore Terran Earl | — | (925) 276 5121 | Electricians | Castro Valley · Alameda County | — | — |
| South Bay Electric | Manuel Jr Ortiz | — | (510) 205 7020 | Electricians | Fremont · Alameda County | — | — |
| South Bay Mechanical | South Bay Mechanical | — | (925) 454 1259 | HVAC | Livermore · Alameda County | — | — |
| Southern Rock | Southern Rock | — | (510) 676 2664 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Southface Construction INC | David Calvin Sylvester | dave@southfaceconstruction.com | (510) 280 4833 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Souto Brothers Landscaping & Concrete Construction INC | David Gonsalves Souto | — | (510) 581 4172 | GC, remodel, ADU | San Lorenzo · Alameda County | — | — |
| Sovana Construction | Aman Pohyar | — | (510) 563 7006 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Sp Construction | Sunil Arvind Patel | devis@sp-construction.com | (408) 202 9125 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Space Age Satellite | Space Age Satellite | — | (510) 773 3322 | Other | Livermore · Alameda County | — | — |
| Space Demolition INC | Gonzalez Raul Robles | — | (510) 377 9782 | Other | Alameda · Alameda County | — | — |
| Spacetone Acoustics INC | Robert Adin Jr Libby | — | (925) 484 3633 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Spark Building Group | Kevin Enrique Sanchez | — | (310) 980 3626 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Sparkle Services INC | Viral Mahesh Patel | info@sparkleservices.com | (510) 376 8800 | Pool | Fremont · Alameda County | — | — |
| Sparkpro Electric | Yeyfer Edgardo Mendez Bolaj | — | (510) 680 6985 | Electricians | Oakland · Alameda County | — | — |
| Sparky Land Electric | Michael Lee Blodgett | — | (510) 532 8930 | Electricians | Oakland · Alameda County | — | — |
| Sparling Construction | Scott Karl Sparling | — | (510) 898 1600 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Special Marble & Granite | Special Marble & Granite | — | (510) 600 7350 | Other | Hayward · Alameda County | — | — |
| Specialized Heating & Air Conditioning | Specialized Heating & Air Conditioning | — | (510) 886 5853 | HVAC | Castro Valley · Alameda County | — | — |
| Specialty Construction Management | Roxanne Fay Smith | info@specialtyconstructionmanagement.com | (888) 717 2170 | GC, remodel, ADU | Pleasanton · Alameda County | — | — |
| Specialty Hardwood Floors | Specialty Hardwood Floors | — | (510) 387 3155 | Other | Alameda · Alameda County | — | — |
| Specialty Inspections Roofing INC | Mark Joseph Kearns | — | (925) 249 9611 | Other roofers | Pleasanton · Alameda County | — | — |
| Specialty Termite INC | Mark Joseph Kearns | — | (925) 249 9611 | Other roofers | Pleasanton · Alameda County | — | — |