| 101 Cast Stone | 101 Cast Stone | sales@caststone.com | (805) 610 9278 | Other | Atascadero · San Luis Obispo County | — | — |
| 101 Excavating LLC | James Mark Scobie | — | (805) 610 5161 | Other | Templeton · San Luis Obispo County | — | — |
| 101 Plumbing | 101 Plumbing | — | (805) 835 9807 | Other | Paso Robles · San Luis Obispo County | — | — |
| 341E A Schmitz General Engineering | 341E A Schmitz General Engineering | — | (805) 459 4266 | Other | Paso Robles · San Luis Obispo County | — | — |
| 3E Construction LLC | Scott Gregory Sepulveda | — | (805) 610 9031 | Other | Paso Robles · San Luis Obispo County | — | — |
| 3rd Gen Pump & Well | 3rd Gen Pump & Well | — | (805) 904 8808 | Other | Pismo Beach · San Luis Obispo County | — | — |
| 4gs Plumbing | Brad Zachary Gilkey | — | (805) 835 3024 | Other | Paso Robles · San Luis Obispo County | — | — |
| 805 Floor Covering | 805 Floor Covering | — | (805) 591 0794 | Other | Paso Robles · San Luis Obispo County | — | — |
| 805 Kustom Tile | 805 Kustom Tile | — | (805) 268 3303 | Other | Nipomo · San Luis Obispo County | — | — |
| 805 Pure Water | 805 Pure Water | info@purewater.com | (805) 321 7873 | Other | Atascadero · San Luis Obispo County | — | — |
| 805 Rooter | 805 Rooter | — | (805) 287 0619 | Other | Nipomo · San Luis Obispo County | — | — |
| A - List Pressure Washing LLC | Cole Anthony Schoenthal | — | (805) 975 5877 | Other | Templeton · San Luis Obispo County | — | — |
| A - Town Media | A - Town Media | — | (805) 423 1523 | Other | Atascadero · San Luis Obispo County | — | — |
| A D Robinson Plastering | A D Robinson Plastering | — | (805) 489 7193 | Other | Arroyo Grande · San Luis Obispo County | — | — |
| A Perfect Plumbing Solution | A Perfect Plumbing Solution | — | (805) 709 6311 | Other | Arroyo Grande · San Luis Obispo County | — | — |
| A T D Window Tinting | Devin Thomas Wayner | — | (805) 239 5887 | Other | Templeton · San Luis Obispo County | — | — |
| A Team Fencing INC | Janel Ryan Armet | — | (805) 238 9165 | Other | Templeton · San Luis Obispo County | — | — |
| A-1 Concrete INC | Mark David Simmons | — | (805) 712 5630 | Other | Atascadero · San Luis Obispo County | — | — |
| A-jay Excavating INC | Jacqueline Ann Dallaire | — | (805) 466 0300 | Other | Atascadero · San Luis Obispo County | — | — |
| Aaaa Engineering Contracting INC | Jesse Duane Arthurs | — | (805) 952 3995 | Other | Templeton · San Luis Obispo County | — | — |
| Aaaa General Engineering INC | Weston Tyler Arthurs | — | (805) 591 9913 | Other | Atascadero · San Luis Obispo County | — | — |
| Abbey Carpet & Floor Of San Luis Obispo | Kalen Loel George | — | (805) 541 5153 | Other | San Luis Obispo · San Luis Obispo County | — | — |
| Abington's Concrete | Abington's Concrete | — | (805) 574 3052 | Other | Arroyo Grande · San Luis Obispo County | — | — |
| Above & Beyond Cleaning Services INC | Lynnette Ann Morrison | — | (916) 704 9370 | Other | Paso Robles · San Luis Obispo County | — | — |
| Above Grade Automation INC | James Kerrigan Ahern | — | (805) 540 5116 | Other | San Luis Obispo · San Luis Obispo County | — | — |
| Absolute Water | Absolute Water | — | (805) 489 0819 | Other | Arroyo Grande · San Luis Obispo County | — | — |
| AC Cor Pavers | AC Cor Pavers | accorpavers@gmail.com | (805) 704 7512 | Other | Atascadero · San Luis Obispo County | — | — |
| Access Limited Construction | Brian Wade Mc Neal | — | (805) 592 2230 | Other | Oceano · San Luis Obispo County | — | — |
| Acme Stucco | Acme Stucco | — | (805) 481 0885 | Other | Grover Beach · San Luis Obispo County | — | — |
| Acoustical Connection | Acoustical Connection | — | (805) 801 1089 | Other | Oceano · San Luis Obispo County | — | — |
| Action Rooter | Action Rooter | — | (805) 541 1333 | Other | San Luis Obispo · San Luis Obispo County | — | — |
| Advanced Fire Protection | James Dale Bye | — | (805) 235 8108 | Other | Atascadero · San Luis Obispo County | — | — |
| Advanced Wireless | Karen Elizabeth Rudnick | — | (805) 922 2252 | Other | San Luis Obispo · San Luis Obispo County | — | — |
| Advantage Technical Services INC | Bryce Orian Griffith | — | (805) 595 2282 | Other | San Luis Obispo · San Luis Obispo County | — | — |
| Al's Septic Pumping Service INC | Robert Matthew Beavers | — | (805) 528 0432 | Other | Los Osos · San Luis Obispo County | — | — |
| Alex Apodaca Plumbing | Alex Apodaca Plumbing | — | (805) 704 2577 | Other | Morro Bay · San Luis Obispo County | — | — |
| All Private Utility Locating INC | Charles Anthony Elisarraras | info@allprivateutilitylocating.com | (805) 610 4043 | Other | Atascadero · San Luis Obispo County | — | — |
| All Star Plumbing | All Star Plumbing | — | (805) 500 3624 | Other | Paso Robles · San Luis Obispo County | — | — |
| All Tech | All Tech | — | (805) 423 7140 | Other | Paso Robles · San Luis Obispo County | — | — |
| Allen's Woodworking | Allen's Woodworking | allenwoodworking2006@gmail.com | (805) 434 1522 | Other | Paso Robles · San Luis Obispo County | — | — |