| Steelhead Construction | Terry Garland Lay | — | (707) 834 6807 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Steelman Builds | Steelman Builds | — | (707) 497 4342 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Stephen Leach | Stephen Leach | me@stephenleach.com | (707) 834 1874 | Other | Trinidad · Humboldt County | — | — |
| Stetzel Builders INC | Jeffrey Radford Stetzel | — | (707) 499 7427 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Steve Morris Logging & Contracting | Todd Tyler Morris | — | (707) 822 8537 | Other | Mc Kinleyville · Humboldt County | — | — |
| Steven Lewis Earthmoving | Steven Lewis Earthmoving | — | (707) 498 1438 | Other | Fortuna · Humboldt County | — | — |
| Steves Septic Service LLC | David Troy Duran | — | (707) 839 2270 | Other | Mc Kinleyville · Humboldt County | — | — |
| Stewart Landscaping Tractor Services | Stewart Milton Schwarz | — | (707) 268 8609 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Stewart Telecommunications | Steven Joseph Lafferty | — | (707) 442 1123 | Other | Eureka · Humboldt County | — | — |
| Stig Construction | Erik Stig Strombeck | — | (707) 499 4422 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Still Waters Plumbing | Still Waters Plumbing | — | (707) 601 7714 | Other | Eureka · Humboldt County | — | — |
| Stodder Electric INC | Tyler Alan Stodder | stodderelectric@hotmail.com | (707) 496 0261 | Electricians | Eureka · Humboldt County | — | — |
| Stonebow Construction | Michael James Kreider | — | (707) 839 1448 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Stonehurst Construction | Christopher Ralph Stone | — | (707) 845 3755 | GC, remodel, ADU | Cutten · Humboldt County | — | — |
| Stop & Go Traffic Control | Wesley Earl Nally | — | (707) 764 3558 | Other | Rio Dell · Humboldt County | — | — |
| Straight Edge Painting | Straight Edge Painting | — | (707) 616 8007 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Straight Flush Plumbing | Straight Flush Plumbing | interested@domainmarket.com | (707) 267 5469 | Other | Eureka · Humboldt County | — | — |
| Strombeck Construction And Painting INC | Steven Mark Strombeck | — | (707) 822 4557 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Stromberg Construction | Brian Leslie Stromberg | — | (707) 498 3744 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Summers Tree Service | John William Summers | — | (315) 317 2024 | Tree | Eureka · Humboldt County | — | — |
| Summit Shield Roofing | Summit Shield Roofing | — | (858) 330-3230 | Other roofers | Coronado · Humboldt County | — | — |
| Sunset Beach Glass And Glazing INC | William Frederick Kimball | — | (562) 735 1987 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Surround You | Surround You | — | (707) 722 7324 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Swanlund Building Design & Remodeling INC | Scott Alan Swanlund | — | (707) 601 4567 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Swanson Decks And Siding | Swanson Decks And Siding | — | (707) 497 9466 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Symbiotic Landscaping | Garrett John Costello | — | (801) 599 9992 | Windows, patio, painters | Mc Kinleyville · Humboldt County | — | — |
| Synergy Humboldt | Brady Michael Gittins | — | (707) 601 6761 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| T And T Roofing | Jerry Leland Thissell | — | (707) 444 9061 | Other roofers | Eureka · Humboldt County | — | — |
| T G Construction | Travis Charles Grinsell | — | (707) 845 6552 | GC, remodel, ADU | Ferndale · Humboldt County | — | — |
| T M Construction | Thomas Allen Morris | — | (707) 498 5255 | GC, remodel, ADU | Ferndale · Humboldt County | — | — |
| T N T Drywall | T N T Drywall | — | (707) 496 9037 | Other | Whitethorn · Humboldt County | — | — |
| T Schneider Enterprises Incorporated | Travis Loren Schneider | — | (707) 445 3001 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| T T Construction | Thomas Wayne Horn | — | (530) 515 4638 | Other | Orleans · Humboldt County | — | — |
| Tall Guy Painting | Tall Guy Painting | — | (707) 498 3415 | Windows, patio, painters | Carlotta · Humboldt County | — | — |
| Taylor Enterprise | Taylor Enterprise | — | (707) 725 2527 | Other | Fortuna · Humboldt County | — | — |
| Tbm Construction | Tony Bernard Iii Mitchell | — | (661) 644-4275 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Tec Home Innovations | Tec Home Innovations | — | (707) 498 1814 | Other | Fortuna · Humboldt County | — | — |
| Ted Larson Painting | Ted Larson Painting | — | (707) 498 7803 | Windows, patio, painters | Arcata · Humboldt County | — | — |
| The Electrician Inc. | The Electrician Inc. | — | (530) 629-4240 | Electricians | Burnt Ranch · Humboldt County | — | — |
| The Fence Doctor | The Fence Doctor | — | (707) 498 3917 | Other | Eureka · Humboldt County | — | — |