| Imperial Custom Painting Company | Imperial Custom Painting Company | — | (805) 295-3091 | Windows, patio, painters | Grover Beach · San Luis Obispo County | — | — |
| Imprint Construction Incorporated | Fred James Iii Jones | — | (805) 710 6509 | GC, remodel, ADU | Arroyo Grande · San Luis Obispo County | — | — |
| Independent Propane Service | Ryan Scott Lindberg | — | (805) 222 0442 | Other | Paso Robles · San Luis Obispo County | — | — |
| Infinite Heating & Cooling | Infinite Heating & Cooling | — | (805) 440 8310 | HVAC | Nipomo · San Luis Obispo County | — | — |
| Infinity Concrete Design INC | Quezada Andres | — | (805) 904 8408 | Other | Oceano · San Luis Obispo County | — | — |
| Ingham Painting INC | Douglas Giles Ingham | — | (805) 481 5127 | Windows, patio, painters | Arroyo Grande · San Luis Obispo County | — | — |
| Ingram & Greene Sanitation | Ingram & Greene Sanitation | — | (805) 226 8170 | Other | Atascadero · San Luis Obispo County | — | — |
| Inhouse Private Security | Inhouse Private Security | info@inhouseprivatesecurity.com | (805) 238-7728 | Alarm and generators | San Luis Obispo · San Luis Obispo County | — | — |
| Inland Pacific Builders INC | Gary Howard Grossman | — | (805) 556 3060 | GC, remodel, ADU | Pismo Beach · San Luis Obispo County | — | — |
| Inman Construction | Charles Mitchell Jr Inman | — | (805) 538 0442 | GC, remodel, ADU | Atascadero · San Luis Obispo County | — | — |
| Innovation Design & Development Construction INC | Ellenie Buenrostro | — | (805) 903 2341 | GC, remodel, ADU | Nipomo · San Luis Obispo County | — | — |
| Innovative Coatings Central Coast INC | Ian Michael Charnley | — | (805) 462 2485 | Windows, patio, painters | Paso Robles · San Luis Obispo County | — | — |
| Innovative Housing Solutions INC | Jason Bartley Blankenship | interested@domainmarket.com | (805) 431 0906 | GC, remodel, ADU | Pismo Beach · San Luis Obispo County | — | — |
| Integrate | Ryan Keith Enoch | — | (805) 242 8210 | Other | Templeton · San Luis Obispo County | — | — |
| Integrity Painting | Integrity Painting | — | (805) 324 1222 | Windows, patio, painters | Templeton · San Luis Obispo County | — | — |
| Integrity Security And Integrated Systems INC | David Randle Condit | — | (805) 462 9150 | Electricians | Atascadero · San Luis Obispo County | — | — |
| Inversion Electric INC | Alexander Holas Havard Griffiths | — | (805) 801 4155 | Electricians | Atascadero · San Luis Obispo County | — | — |
| Ironwood Finish Carpentry | Ironwood Finish Carpentry | — | (805) 610 9482 | GC, remodel, ADU | Paso Robles · San Luis Obispo County | — | — |
| Irvin Air | Irvin Air | — | (805) 423 8046 | HVAC | Paso Robles · San Luis Obispo County | — | — |
| Islandboy Painting | Islandboy Painting | — | (831) 970 9052 | Windows, patio, painters | San Miguel · San Luis Obispo County | — | — |
| Italfloor Covering | Italfloor Covering | — | (805) 440 6365 | Other | San Luis Obispo · San Luis Obispo County | — | — |
| Itd Construction INC | Jason James Stuart | — | (805) 610 8279 | GC, remodel, ADU | Paso Robles · San Luis Obispo County | — | — |
| Iwerks Construction Company | David Casey Iwerks | — | (805) 766 3000 | GC, remodel, ADU | Arroyo Grande · San Luis Obispo County | — | — |
| Izzy Plumbing | Izzy Plumbing | — | (805) 264 3058 | Other | San Luis Obispo · San Luis Obispo County | — | — |
| Izzy's Installations And Colony Floors | Izzy's Installations And Colony Floors | — | (805) 459 9520 | Other | Templeton · San Luis Obispo County | — | — |
| J & J Concrete Construction | Jesus Javier Anguiano | — | (805) 296 4290 | Other | Paso Robles · San Luis Obispo County | — | — |
| J & M Welding INC | Mitchell Joaquin Madrid | — | (805) 440 3161 | Other | Paso Robles · San Luis Obispo County | — | — |
| J 2 Construction Company | Jose Gonzalez | — | (805) 286 8903 | GC, remodel, ADU | Paso Robles · San Luis Obispo County | — | — |
| J A Hunter Construction INC | Russell Thomas Hunter | — | (805) 543 4209 | GC, remodel, ADU | San Luis Obispo · San Luis Obispo County | — | — |
| J A Rudnick Builders | J A Rudnick Builders | — | (805) 748 2717 | GC, remodel, ADU | Templeton · San Luis Obispo County | — | — |
| J A Wouters INC | Justin Andrew Wouters | — | (805) 704 6864 | Other | Templeton · San Luis Obispo County | — | — |
| J Arnold Fencing INC | Joseph John Arnold | — | (805) 610 0036 | Other | Santa Margarita · San Luis Obispo County | — | — |
| J B Electric Services | John Eric Blum | — | (805) 452 8985 | Electricians | Nipomo · San Luis Obispo County | — | — |
| J B L Construction | Jeffery Brian Lampman | — | (805) 441 8110 | GC, remodel, ADU | Morro Bay · San Luis Obispo County | — | — |
| J B's Custom Woodworking | J B's Custom Woodworking | — | (805) 473 3017 | Other | Oceano · San Luis Obispo County | — | — |
| J Beller Construction INC | Jonathan Edward Beller | — | (805) 471 3980 | GC, remodel, ADU | Arroyo Grande · San Luis Obispo County | — | — |
| J Bruce Kies - Contractor/consultant | J Bruce Kies - Contractor/consultant | — | (805) 591 0549 | GC, remodel, ADU | Paso Robles · San Luis Obispo County | — | — |
| J C Construction | Jonn Gerry Christian | — | (805) 835 8997 | GC, remodel, ADU | Paso Robles · San Luis Obispo County | — | — |
| J C Construction | Jason James Carmichael | — | (805) 459 2048 | GC, remodel, ADU | Los Osos · San Luis Obispo County | — | — |
| J Cat Concrete | J Cat Concrete | — | (805) 801 7463 | Other | Oceano · San Luis Obispo County | — | — |