| J&m's Electric LLC | Marco Antonio Magana | — | (714) 402 6474 | Electricians | Jurupa Valley · Riverside County | — | — |
| J&n Construction Innovation Corp | Edgar Covarrubias Gonzalez | — | (951) 230 3605 | GC, remodel, ADU | Perris · Riverside County | — | — |
| J&n Plumbing INC | Justin Ray Fawver | — | (951) 477 7540 | Other | Lake Elsinore · Riverside County | — | — |
| J&r Elite Roofing | Renato Jr Romero | jnreliteroofing@gmail.com | (951) 902 3258 | Other roofers | Moreno Valley · Riverside County | — | — |
| J&s Electrical Systems | Joseph Stephen Sinay Esturban | — | (951) 573 3256 | Electricians | Riverside · Riverside County | — | — |
| J&s Remodel And Restoration | Andrew Ryan Ortuno | — | (951) 542 2188 | GC, remodel, ADU | Moreno Valley · Riverside County | — | — |
| J&t Plumbing Pro's INC | Timothy Steven Whitcomb | — | (800) 265 2045 | Other | Nuevo · Riverside County | — | — |
| J's All Pro Electric INC | Rios Josue Espinosa | — | (951) 230 4269 | Electricians | Wildomar · Riverside County | — | — |
| J's Concrete Services | Dany Atallah | — | (951) 316 3889 | Other | Corona · Riverside County | — | — |
| J's Electric | Jesus Salazar | — | (714) 472 3801 | Electricians | Corona · Riverside County | — | — |
| J's Electric | Gerardo Jerry Gonzalez | — | (626) 419 0648 | Electricians | Jurupa Valley · Riverside County | — | — |
| J's Heating Air Conditioning And General Contractor | Galeb Miguel El Johary | — | (951) 640 8177 | HVAC | Riverside · Riverside County | — | — |
| J*c Remodeling & Construction | Cruzbel Alderete-Silva | — | (949) 386 9580 | GC, remodel, ADU | Corona · Riverside County | — | — |
| J-electric | Jose Cruz Hernandez | — | (951) 452 5679 | Electricians | Moreno Valley · Riverside County | — | — |
| J-mac Construction Co | Thomas S Mc Lean | — | (760) 393 1799 | GC, remodel, ADU | Desert Hot Springs · Riverside County | — | — |
| J. Vera Masonry | J. Vera Masonry | — | (951) 420 4680 | Other | Perris · Riverside County | — | — |
| J.adams Air Conditioning Heating And Plumbing Corp | Justin Adam Spencer | — | (909) 233 5030 | HVAC | Riverside · Riverside County | — | — |
| J.e. Valdez Construction | Juan Enrique Valdez Dozal | — | (760) 880 6396 | GC, remodel, ADU | Palm Desert · Riverside County | — | — |
| J.m.rice INC | Jonathan Michael Rice | — | (951) 756 0934 | Electricians | Norco · Riverside County | — | — |
| J23 INC | Jason Keith Kyawmyint | — | (714) 981 1041 | Other | Wildomar · Riverside County | — | — |
| J3 Electrical LLC | James William Iii Huffman | — | (916) 303 3302 | Electricians | Norco · Riverside County | — | — |
| J3 Enterprises INC | Jacob Andrew Beaty | inquiries@j3-enterprises.com | (760) 578 0616 | GC, remodel, ADU | Thousand Palms · Riverside County | — | — |
| Ja Custom Concrete | Ja Custom Concrete | — | (949) 246 0322 | Other | San Jacinto · Riverside County | — | — |
| Ja Maqueda Framing Specialist | Ja Maqueda Framing Specialist | — | (760) 917 9675 | Other | Wildomar · Riverside County | — | — |
| Jab Industries INC | John Anton Brende | — | (760) 610 2650 | GC, remodel, ADU | Indian Wells · Riverside County | — | — |
| Jac Constructors INC | Jose Juan Gonzalez | — | (760) 200 6615 | GC, remodel, ADU | La Quinta · Riverside County | — | — |
| Jack Delaney Pool And Spa Service | Jack Neal Delaney | — | (951) 218 5913 | Pool | Wildomar · Riverside County | — | — |
| Jack Diaz | Jack Diaz | — | (760) 321 2544 | Tree | Cathedral City · Riverside County | — | — |
| Jack Fielding Design Engineering & Building INC | Jack Edward Fielding | — | (951) 623 9735 | GC, remodel, ADU | Perris · Riverside County | — | — |
| Jack Frost Heating And Cooling INC | Ralph Duane Iii Hayes | — | (951) 970 3793 | HVAC | Lake Elsinore · Riverside County | — | — |
| Jack Gardner Jr | Jack Gardner Jr | — | (951) 212 9408 | GC, remodel, ADU | Norco · Riverside County | — | — |
| Jack Liu | Jack Liu | — | (626) 833 4851 | Other | Riverside · Riverside County | — | — |
| Jack Tracy Builders | Jack Tracy Builders | — | (805) 377 7584 | GC, remodel, ADU | La Quinta · Riverside County | — | — |
| Jackhammer Paving Solutions | Jonathan Alvarez | — | (562) 665 0023 | Other | Menifee · Riverside County | — | — |
| Jackson Electric Enterprises INC | Keelin Bryan Jackson | — | (760) 408 2444 | Electricians | Rancho Mirage · Riverside County | — | — |
| Jacob Cabinets | Jacob Cabinets | — | (562) 999 6713 | Other | Corona · Riverside County | — | — |
| Jacob Chavez Construction | Jacob Stephen Chavez | — | (562) 682 2180 | GC, remodel, ADU | Murrieta · Riverside County | — | — |
| Jacob D Plumbing | Joseph Moses Williams | — | (562) 548 9383 | Other | Murrieta · Riverside County | — | — |
| Jacob D Plumbing | Daniel Lopez | — | (562) 548 9383 | Other | Murrieta · Riverside County | — | — |
| Jacob Dishman Construction | Jacob Jackson Dishman | — | (951) 543 8784 | GC, remodel, ADU | Calimesa · Riverside County | — | — |