| Constructors Hawaii INC | Constructors Hawaii INC | info@constructorshawaii.com | (808) 848-2455 | GC, remodel, ADU | Honolulu · Honolulu County | — | — |
| Contech Engineering INC | Contech Engineering INC | sales@contechengineering.com | — | GC, remodel, ADU | Other County | — | — |
| Contech Services INC | Contech Services INC | — | (714) 557-6425 | Other | Honolulu · Honolulu County | — | — |
| Contractor's Equipment & Service Corp | Contractor's Equipment & Service Corp | traciek@cescorphi.com | (808) 676-7566 | Other | Waipahu · Honolulu County | — | — |
| Control Freaks Hawaii INC | Control Freaks Hawaii INC | — | (808) 874-8019 | Electricians | Kahului · Maui County | — | — |
| Cook Coatings INC | Cook Coatings INC | jane@company.com | — | Other roofers | Honolulu · Honolulu County | — | — |
| Cool Air INC | Cool Air INC | — | (904) 389-3646 | HVAC | Waipahu · Honolulu County | — | — |
| Cool Stone LLC | Cool Stone LLC | chris@coolstone.com | (425) 785-1998 | Other | Honolulu · Honolulu County | — | — |
| Cooling Hawaii LLC | Cooling Hawaii LLC | info@coolinghawaii.com | (808) 727-2777 | HVAC | Puunene · Maui County | — | — |
| Cooling Solutions Hawaii LLC | Cooling Solutions Hawaii LLC | info@coolingsolutionshawaii.com | (808) 638-3633 | HVAC | Ewa Beach · Honolulu County | — | — |
| Copper Electric INC | Copper Electric INC | copperel@telus.net | (780) 221-0755 | Electricians | Haiku · Maui County | — | — |
| Cor-Ray Painting Co | Cor-Ray Painting Co | sales@corraypainting.com | — | Windows, patio, painters | Honolulu · Honolulu County | — | — |
| Cornerstone Properties | Cornerstone Properties | — | (808) 484-1211 | Property managers | Aiea · Honolulu County | — | — |
| Correa Electric | Correa Electric | — | (808) 345-3989 | Electricians | Kailua-Kona · Hawaii County | — | — |
| Correia Corporation | Correia Corporation | firstname@correia.com | — | GC, remodel, ADU | Hilo · Hawaii County | — | — |
| Cosco Air Conditioning & Refrigeration | Cosco Air Conditioning & Refrigeration | — | (808) 871-6285 | HVAC | Kahului · Maui County | — | — |
| Cosco Air Conditioning & Refrigeration | Cosco Air Conditioning & Refrigeration | — | (808) 632-2153 | HVAC | Lihue · Kauai County | — | — |
| Cosco Air Conditioning & Refrigeration | Cosco Air Conditioning & Refrigeration | — | (808) 845-2234 | HVAC | Honolulu · Honolulu County | — | — |
| Cr Ramos Electric | Cr Ramos Electric | — | (808) 822-9020 | Electricians | Kapaʻa · Kauai County | — | — |
| Crabbe Services LLC | Crabbe Services LLC | — | (808) 345-5896 | Other | Kamuela · Hawaii County | — | — |
| Craig's Air Conditioning | Craig's Air Conditioning | service@craigsair.com | (808) 682-0970 | HVAC | Kona · Hawaii County | — | — |
| Crane Construction Company LLC | Crane Construction Company LLC | resumes@craneconstruction.com | — | GC, remodel, ADU | Other County | — | — |
| Creative Building Concepts LLC | Creative Building Concepts LLC | interested@domainmarket.com | (888) 694-6735 | GC, remodel, ADU | Kailua · Honolulu County | — | — |
| Creative Design Signs LLC | Creative Design Signs LLC | — | (808) 269-8621 | Other | Haiku · Maui County | — | — |
| Creative Tile Corp | Creative Tile Corp | info@creative-tile.com | — | Other | Honolulu · Honolulu County | — | — |
| Crescent Homes Maui | Crescent Homes Maui | — | (808) 727-1162 | EV chargers | Maui · Maui County | — | — |
| Cubellis Plumbing LLC | Cubellis Plumbing LLC | — | (808) 226-9361 | Other | Honolulu · Honolulu County | — | — |
| Curtis Law Construction | Curtis Law Construction | — | (808) 246-0676 | Other roofers | Lihue · Kauai County | — | — |
| Cushnie Construction Company INC | Cushnie Construction Company INC | — | (808) 332-9000 | GC, remodel, ADU | Kalaheo · Kauai County | — | — |
| Custom Cooling Inc. | Custom Cooling Inc. | service@customcoolingkauai.com | (808) 635-4112 | HVAC | Lihue · Kauai County | — | — |
| Custom Electric LLC | Custom Electric LLC | estimating@customelectric.com | (587) 272-1800 | Electricians | Waialua · Honolulu County | — | — |
| Custom Mechanical Design LLC | Custom Mechanical Design LLC | info@custommechanicaldesign.com | (801) 296-2600 | HVAC | Kailua · Honolulu County | — | — |
| Cutting Edge Tile INC | Cutting Edge Tile INC | interested@domainmarket.com | (888) 694-6735 | Other | Aiea · Honolulu County | — | — |
| Cv Construction LLC | Cv Construction LLC | — | (949) 705-0400 | GC, remodel, ADU | Honolulu · Honolulu County | — | — |
| D & C Construction INC | D & C Construction INC | — | (949) 679-5800 | GC, remodel, ADU | Kaneohe · Honolulu County | — | — |
| Da Kine Handyman LLC | Da Kine Handyman LLC | info@dakinehandyman.com | (808) 634-5409 | GC, remodel, ADU | Kalaheo · Kauai County | — | — |
| Da Pool Guy LLC | Da Pool Guy LLC | — | (808) 652-5669 | Pool | Kauai · Kauai County | — | — |
| Da Power Electric | Da Power Electric | info@dapowerelectric.com | (808) 868-6035 | Electricians | Kihei · Maui County | — | — |
| Dakine Air Conditioning | Dakine Air Conditioning | — | (808) 276-2319 | HVAC | Kihei · Maui County | — | — |
| Daniel Egeland | Daniel Egeland | post@teamegeland.no | — | GC, remodel, ADU | Other County | — | — |