| Small World Tree Company | James Elliott Cairnes | — | (415) 455 0909 | Tree | San Anselmo · Marin County | — | — |
| Smart Tile INC | Pedro Jr Delcides Borges | — | (510) 253 5858 | Other | San Rafael · Marin County | — | — |
| Smc | Seain Daniel Mccann | — | (415) 259 9229 | GC, remodel, ADU | Novato · Marin County | — | — |
| Smf Glass INC | Stephen Mitchell Fie | — | (415) 453 6322 | Windows, patio, painters | San Rafael · Marin County | — | — |
| Smiley Construction Co | Thomas Robert Smiley | — | (415) 454 2988 | GC, remodel, ADU | Ross · Marin County | — | — |
| Smollen The Builder INC | Craig Scott Smollen | — | (415) 271 0568 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Sneed And Company Construction INC | Richard Duke Sneed | — | (415) 453 2493 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Snow Construction | James Franklin Snow | — | (415) 244 2676 | GC, remodel, ADU | Fairfax · Marin County | — | — |
| So Electric INC | Mostaghal Soheil | — | (707) 694 3785 | Electricians | Novato · Marin County | — | — |
| Solarcraft Services INC | Roy Vincent Lembi | — | (415) 382 7717 | Electricians | Novato · Marin County | — | — |
| Solarports Development | Joseph Stolp Iv Sherer | — | (415) 888 4000 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Solid Craft Construction & Painting INC | Jose Luis Armando Velasquez Sanchez | — | (415) 720 4830 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Sonoma-Marin Home Inspections | Sonoma-Marin Home Inspections | — | (707) 570-0408 | Inspectors | Petaluma · Marin County | — | — |
| Sorrells Construction | Stephen Arnett Sorrells | — | (415) 847 0087 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Sotnikof Remodeling Solutions | Sotnikof Remodeling Solutions | — | (415) 685 9707 | GC, remodel, ADU | Novato · Marin County | — | — |
| Sound 22 | Sound 22 | — | (415) 332 1298 | Other | Novato · Marin County | — | — |
| Soundvision Systems INC | Herbert Scott Sullivan | — | (415) 456 7000 | Other | Novato · Marin County | — | — |
| Space Makers LLC | Kodras Jorgo | — | (415) 717 6724 | Windows, patio, painters | Novato · Marin County | — | — |
| Specialty Finishes Window Coverings | Tristan Nicholas Mermin | — | (415) 453 4722 | Other | San Quentin · Marin County | — | — |
| Spectre8 | Geoffrey Adam Rosenblatt | hello@spectre8.com | (415) 683 1019 | GC, remodel, ADU | Sausalito · Marin County | — | — |
| Spectrum Av LLC | Alan Hutchings | — | (415) 322 1213 | Other | Mill Valley · Marin County | — | — |
| Spellbound Construction | David William Hill | — | (415) 302 5622 | GC, remodel, ADU | Novato · Marin County | — | — |
| Spire Architecture INC | Doron Jacob Dreksler | — | (415) 275 3405 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Spnr Built INC | Mark Spinner Forsythe | — | (415) 793 1161 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Spoor Masonry & Tile INC | Robert Fredrick Spoor | — | (415) 457 3321 | Other | San Rafael · Marin County | — | — |
| Square N Compass Building | Square N Compass Building | — | (415) 686 2997 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Ss Group Services Corporation | William De Camargo Silva | — | (510) 672 6553 | GC, remodel, ADU | Greenbrae · Marin County | — | — |
| Staar Design Services | Terence Frank Jevitt | — | (415) 408 8817 | GC, remodel, ADU | Point Reyes Station · Marin County | — | — |
| Starving Plumbers | Richard Eric Slaugh | starvingplumbers@gmail.com | (415) 925 1234 | GC, remodel, ADU | Kentfield · Marin County | — | — |
| Stay Covered Builders INC | Theodore Todd Fischer | — | (650) 440 9295 | GC, remodel, ADU | Novato · Marin County | — | — |
| Steckler-pacific Co INC | David Jerome Steckler | — | (415) 332 5510 | GC, remodel, ADU | Sausalito · Marin County | — | — |
| Steelcore Builders INC | Peter Ghodsian | %20info@steelcorebuilders.com | (415) 331 0525 | GC, remodel, ADU | Sausalito · Marin County | — | — |
| Steere Building And Woodworking | Steere Building And Woodworking | — | (415) 613 7434 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Stefan Steinbach | Stefan Steinbach | — | (415) 453 7322 | Other | San Rafael · Marin County | — | — |
| Stephen Fitzsimon | Stephen Fitzsimon | — | (415) 309 7095 | Other | Larkspur · Marin County | — | — |
| Stephen Freeman Construction | Stephen Thomas Jr Freeman | — | (415) 328 0706 | Electricians | Novato · Marin County | — | — |
| Stephen L Pasquan | Stephen L Pasquan | — | (415) 435 8100 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Stephen Pasquan | Stephen Pasquan | — | (415) 435 8100 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Stephen R Bouchard DBA Bouchard Construction | Stephen Randall Bouchard | — | (415) 717 6573 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Stephenson-richman Electrical | Marc Gary Stephenson-richman | — | (415) 559 4705 | Electricians | Novato · Marin County | — | — |