| 'final Touch' Painting | 'final Touch' Painting | — | (415) 601 1017 | Windows, patio, painters | San Mateo · San Mateo County | — | — |
| 0303 Construction INC | Juan Manuel Ortega | — | (650) 452 2720 | GC, remodel, ADU | Pacifica · San Mateo County | — | — |
| 10-4 Millwork | Roger De Castro Ferreira | — | (650) 863 2333 | Other | San Mateo · San Mateo County | — | — |
| 101 Mobility | Raul Emmanuel Navarro | — | (650) 614 1533 | GC, remodel, ADU | Burlingame · San Mateo County | — | — |
| 110/220v Electric Co | Bart Steven Speccia | — | (650) 784 1886 | Electricians | San Bruno · San Mateo County | — | — |
| 12 Stone Construction Co | Caesar Carlos Evangelista | — | (352) 217 6490 | GC, remodel, ADU | San Bruno · San Mateo County | — | — |
| 29 Dollar Plumbing | 29 Dollar Plumbing | — | (650) 999 9929 | Other | Burlingame · San Mateo County | — | — |
| 2B Living INC | Patricia Wynne Baskin | — | (650) 763 8552 | GC, remodel, ADU | San Carlos · San Mateo County | — | — |
| 2nd Generation Development INC DBA Bay Area Pervious Concrete | Liguori David | — | (650) 596 0683 | GC, remodel, ADU | San Carlos · San Mateo County | — | — |
| 3 A Plumbing | 3 A Plumbing | — | (415) 404 1400 | Other | San Bruno · San Mateo County | — | — |
| 3 C I Systems Integration INC | Anne Cunningham Campbell | — | (415) 285 2629 | Other | Woodside · San Mateo County | — | — |
| 3 E Solutions INC | Frank Joseph Sisca | — | (650) 773 2524 | Electricians | San Mateo · San Mateo County | — | — |
| 3 J Electrical | Junling Zeng | — | (415) 568 0719 | Electricians | Pacifica · San Mateo County | — | — |
| 3 N 1 Construction INC | Mak Ka Wang | info@nconstruction.com | (415) 310 8878 | GC, remodel, ADU | South San Francisco · San Mateo County | — | — |
| 3 Power Electric INC | Alen Naun Rodriguez Flores | info@powerelectric.com | (650) 759 0043 | Electricians | Daly City · San Mateo County | — | — |
| 328 Construction INC | Zhao Young | — | (415) 823 7119 | Electricians | Daly City · San Mateo County | — | — |
| 365 Plumbing & Rooter | 365 Plumbing & Rooter | — | (415) 368 3450 | Other | Daly City · San Mateo County | — | — |
| 369 Construction Co INC | Qi Hua| Zhao Qi-hua Zhao | — | (415) 828 1131 | GC, remodel, ADU | Daly City · San Mateo County | — | — |
| 3J Construction | Sandy Orquiza Alvarez | impallari@gmail.com | (415) 794 0225 | GC, remodel, ADU | Daly City · San Mateo County | — | — |
| 3J Tile INC | Jose Roberto Juarez | — | (650) 399 6819 | Other | San Carlos · San Mateo County | — | — |
| 415 Design+build | Larry Ely Fonseca | — | (415) 347 5627 | GC, remodel, ADU | Brisbane · San Mateo County | — | — |
| 415 Drywall | 415 Drywall | — | (408) 722 2069 | Other | San Bruno · San Mateo County | — | — |
| 5 Star Building Maintenance LLC | Jace Deron Mcbee | — | (650) 533 4595 | Other | San Bruno · San Mateo County | — | — |
| 88 Builders | Weiying Zhu | — | (415) 264 5807 | GC, remodel, ADU | Daly City · San Mateo County | — | — |
| A & A General Building Construction Inc. | Timothy Viloria Anunciacion | — | (650) 757 7600 | GC, remodel, ADU | Daly City · San Mateo County | — | — |
| A & A Landscape INC | Jose Angel Quintero | — | (650) 368 5859 | Windows, patio, painters | Redwood City · San Mateo County | — | — |
| A & B Roofing INC | Ryan Allen Worthington | — | (650) 551 7029 | Other roofers | Emerald Hills · San Mateo County | — | — |
| A & C United Construction | Timothy Ting-Di Wu | — | (415) 347 1368 | GC, remodel, ADU | South San Francisco · San Mateo County | — | — |
| A & D Glass Depot INC | Andy Wing Jong Lee | — | (650) 755 4501 | Windows, patio, painters | Colma · San Mateo County | — | — |
| A & D Welding INC | James Anthony Aveggio | web@adwelding.com | (650) 593 4040 | Other | San Carlos · San Mateo County | — | — |
| A & G Hardwood Flooring | A & G Hardwood Flooring | — | (650) 921 0998 | Other | San Mateo · San Mateo County | — | — |
| A & K Electric | Sukhpal Singh Sangha | — | (650) 642 1666 | Electricians | San Mateo · San Mateo County | — | — |
| A & M Plumbing | A & M Plumbing | — | (408) 828 6446 | Other | Belmont · San Mateo County | — | — |
| A & Q Electrical INC | Alan Shiwei Ng | — | (415) 623 9930 | Electricians | South San Francisco · San Mateo County | — | — |
| A & R Termite Control | A & R Termite Control | — | (650) 347-9512 | Pest, tile roofs | San Mateo · San Mateo County | — | — |
| A & S Electric LLC | Anthony Fai Chau | — | (510) 376 9897 | Electricians | South San Francisco · San Mateo County | — | — |
| A & S Quality Builders Company | Kryukov Sergey | — | (415) 279 5705 | GC, remodel, ADU | South San Francisco · San Mateo County | — | — |
| A - 1 Hauling | A - 1 Hauling | — | (650) 270 5746 | Other | South San Francisco · San Mateo County | — | — |
| A - Mac Construction | Adrian Joseph Mc Glinchey | — | (415) 601 4698 | GC, remodel, ADU | San Mateo · San Mateo County | — | — |
| A 1 Budget Plumbing | A 1 Budget Plumbing | — | (650) 291 3743 | Other | Burlingame · San Mateo County | — | — |