| Imp Electrical & Automation Solutions LLC | Parlas Mahir | — | (510) 862 9964 | Electricians | Hayward · Alameda County | — | — |
| Impact Pro Construction | Craig M Grimm | hello@impactproconstruction.com | (415) 996 7001 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Imperial Insulation LLC | Francisco Ramon Ayala | interested@domainmarket.com | (510) 603 0224 | Other | San Leandro · Alameda County | — | — |
| Implicit Construction | Jonathan Miguel Gomez | — | (510) 750 9292 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Impressive Brothers Builder INC | Zhiming Guo | — | (510) 689 7860 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Impulse Pro | Impulse Pro | — | (818) 987 8400 | HVAC | Fremont · Alameda County | — | — |
| Imx INC | Patrick Newman Mac Intyre | — | (510) 715 3999 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| In & Out Electric INC | Daghighian Mazdak | maz@inoutelectric.com | (408) 390 5494 | Electricians | Union City · Alameda County | — | — |
| In N Out Flooring | In N Out Flooring | — | (510) 289 7677 | Other | Oakland · Alameda County | — | — |
| In Style Flooring INC | Davis Nguyen | — | (415) 218 9043 | Other | Oakland · Alameda County | — | — |
| Incc | Alonso Alex | — | (503) 575 1990 | Electricians | Oakland · Alameda County | — | — |
| Inclan Property Renovations | Inclan Property Renovations | — | (510) 746 6166 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Independent Electrical Testing | Roger Kenneth Houtz | — | (925) 447 6577 | Electricians | Livermore · Alameda County | — | — |
| Indfoss Refrigeration INC | Tejinder Singh Bharaj | indfossinc@gmail.com | (650) 701-4555 | HVAC | Union City · Alameda County | — | — |
| Indus Pole Star Group INC | Krishna K Chockalingam | — | (510) 200 5108 | Other | Hayward · Alameda County | — | — |
| Industrial Motor Control Solutions INC | Britt Lee Wilson | — | (925) 518 2605 | Electricians | Livermore · Alameda County | — | — |
| Infinity Mechanical INC | Paul Matthew Macpherson | — | (888) 464 8221 | HVAC | Fremont · Alameda County | — | — |
| Infocus Construction INC | Trac Van Le | — | (510) 529 5169 | GC, remodel, ADU | Livermore · Alameda County | — | — |
| Infrastructure Development | Infrastructure Development | — | (510) 856 8439 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Infrastructure Development Corporation | Gary Arthur Gatterman | — | (510) 856 8439 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Inner City Demolition INC | James Joseph Campanella | — | (510) 382 0100 | Other | Dublin · Alameda County | — | — |
| Innocon | Raveshti Ramin Afnani | — | (510) 552 5764 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Innovate Stone Design INC | Bradlee Leodan Xec-Xec | — | (510) 220 2029 | Other | San Leandro · Alameda County | — | — |
| Innovated Electric | Gonzales Carlos | — | (650) 305 0483 | Electricians | Hayward · Alameda County | — | — |
| Innovation Construction INC | Andrew Alexander Puchkov | — | (510) 777 1877 | Other roofers | San Leandro · Alameda County | — | — |
| Innovation Electric INC | Andrew Alexander Puchkov | — | (510) 827 1007 | Electricians | Alameda · Alameda County | — | — |
| Innovative Building INC | Jesus Jr Arellano | — | (510) 209 4942 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Innovative Woodworks Incorporated | Nirmal Kumar | — | (510) 265 0800 | GC, remodel, ADU | Union City · Alameda County | — | — |
| Insign Electric | Andras Dallos | — | (925) 460 8525 | Electricians | Pleasanton · Alameda County | — | — |
| Insignia Designs | Carol Lynne Moberg | — | (925) 462 3000 | Other | Pleasanton · Alameda County | — | — |
| Inspection Pros - East Bay San Francisco And Silicon Valley | Inspection Pros - East Bay San Francisco And Silicon Valley | — | (925) 838-5959 | Inspectors | Alameda · Alameda County | — | — |
| Instalan Systems INC | Michael Rosado Rivera | — | (510) 440 1010 | Other | Fremont · Alameda County | — | — |
| Installit INC | James Robert Korhummel | — | (510) 918 1028 | Other | Newark · Alameda County | — | — |
| Instant Neon | Instant Neon | — | (510) 773 9031 | Electricians | Pleasanton · Alameda County | — | — |
| Instone Manufacturing INC | Paul Antonio Charondo | — | (510) 351 1900 | Other | San Leandro · Alameda County | — | — |
| Insulation Specialties INC | Vickie Skolnick | — | (925) 401 5200 | Other | Pleasanton · Alameda County | — | — |
| Insultech Contracting LLC | Kimber Lane Dittmore | info@insultechcontracting.com | (510) 221 9087 | Other | Livermore · Alameda County | — | — |
| Intec Solutions INC | Christopher Lance Hall | impallari@gmail.com | (925) 443 4683 | Electricians | Livermore · Alameda County | — | — |
| Integra Construction Services INC | Alexander Michael Giammona | — | (925) 425 9103 | GC, remodel, ADU | Pleasanton · Alameda County | — | — |
| Integrated Concrete Construction INC | William Ernesto Burgos | — | (510) 200 9592 | Other | Hayward · Alameda County | — | — |