| Cool Solutions (UK) Limited | Transport & logistics | 1999 |
| Coolships 3 Limited | Extraterritorial | 2016 |
| Coolships 4 Limited | Administrative & support | 2020 |
| Coolships UK Limited | Extraterritorial | 2009 |
| Cooper Construction Services Limited | Construction | 2004 |
| Cooper Forklift Services Limited | Manufacturing | 2022 |
| Cooper Residential Ltd | Real estate | 2025 |
| Cooperation Hull Ltd | Other services | 2024 |
| Coopers HGV & Plant Services Ltd | Manufacturing | 2024 |
| Copaged Investments Limited | Wholesale & retail | 2024 |
| Copernus Limited | Wholesale & retail | 2010 |
| Coppa Contractors Ltd | Construction | 2025 |
| Coppergate Land and Property Ltd | Other services | 2023 |
| Coppergate Training Limited | Education | 2024 |
| Cops Construction Limited | Construction | 2025 |
| Cora Practitioner Services Limited | Health & social care | 2017 |
| Cord Solutions Limited | Administrative & support | 2025 |
| Core AI Labs Ltd | Information & communication | 2025 |
| Core Construction (Hull) Limited | Construction | 2018 |
| Core Energy Systems Limited | Manufacturing | 2020 |
| Core Unified IT Consultancy Ltd | Information & communication | 2026 |
| Cori Services Ltd | Manufacturing | 2024 |
| Corium Treasury Limited | Professional & scientific | 2018 |
| Corner Cafe Hessle Limited | Hospitality | 2024 |
| Corner Shop HU3 Ltd | Wholesale & retail | 2026 |
| Cornerhouse (Yorkshire) | Health & social care | 1991 |
| Corporate Travel International Limited | Administrative & support | 2013 |
| Correlate Financial Management Ltd | Professional & scientific | 2013 |
| Corrupted Competitions Ltd | Wholesale & retail | 2025 |
| Coskunsu Properties Limited | Real estate | 2019 |
| Cosmetic & Family Dentistry (Hull) Limited | Health & social care | 2020 |
| Cosmetologist Hull Limited | Wholesale & retail | 2022 |
| Cosmic Taverns Ltd | Hospitality | 2025 |
| Cosmo Community CIC | Agriculture & fishing | 2018 |
| Cosmos Data Technologies (UK) Limited | Wholesale & retail | 2023 |
| Cosoulda Limited | Hospitality | 2026 |
| Costa Delivery Ltd | Transport & logistics | 2025 |
| Costareed Ltd | Hospitality | 2024 |
| Cosy Koalas Nursery Ltd | Education | 2026 |
| Cote Farm Roos Limited | Agriculture & fishing | 2021 |
| Cotruta Limited | Construction | 2021 |
| Cottage Green (Cottingham) Residents Management Company Limited | Households | 2002 |
| Cottage Industry Events Limited | Administrative & support | 2011 |
| Cottage Industrys Limited | Hospitality | 2009 |
| Cottingham Brickwork Specialist Ltd | Construction | 2024 |
| Cottingham Property Investments Limited | Real estate | 2009 |
| Coulson.Main Ltd | Construction | 2011 |
| Count on US Bookkeeping and Accountancy Ltd | Professional & scientific | 2020 |
| Country Care Holderness Ltd | Health & social care | 2024 |
| Countryside Markets Limited | Real estate | 2003 |
| Countrywise Water Coolers (Holdings) Ltd | Administrative & support | 2017 |
| Countrywise Water Coolers Ltd | Administrative & support | 1991 |
| County Car Sales Hull Limited | Wholesale & retail | 2019 |
| Coupland Rigging Ltd | Construction | 2024 |
| Courier Ease Ltd | Transport & logistics | 2025 |
| Courtford Balloons Ltd | Transport & logistics | 2021 |
| Courtyard Hospitality Ltd | Hospitality | 2024 |
| Cove Dining Ltd | Hospitality | 2026 |
| Coverwell Flooring Services Ltd | Construction | 2022 |
| Cowden Landholdings Limited | Real estate | 2020 |
| Cowman Solutions Ltd | Construction | 2026 |
| Coyle Fitness Limited | Other services | 2019 |
| Coyle Health & Well-Being Limited | Health & social care | 2017 |
| Coyle Industries Ltd | Manufacturing | 2020 |
| Coyle-Uk Ltd | Construction | 2025 |
| Cozyhouseshull Limited | Hospitality | 2022 |
| CP Hospitality Solutions Limited | Hospitality | 2026 |
| CPD Direct EOT Limited | Financial services | 2025 |
| CPD Direct Limited | Financial services | 2015 |
| CPF Pet Foods Ltd | Wholesale & retail | 2025 |
| CPH Renewables Ltd | Construction | 2020 |
| CPR Components (Hull) Ltd | Water & waste | 2017 |
| CPS Leisure (Hull) Limited | Arts & recreation | 2023 |
| CPW Accounting Limited | Professional & scientific | 2025 |
| CR 8800 Limited | Hospitality | 2025 |
| CR Estates Limited | Real estate | 2017 |
| CR1 Holdings Limited | Financial services | 2020 |
| Crab Plus Limited | Wholesale & retail | 2023 |
| Crabtastic Ltd | Hospitality | 2026 |
| Craft Hull Limited | Hospitality | 2026 |
| Craft Kebab Limited | Hospitality | 2025 |
| Craft King Ltd | Manufacturing | 2018 |
| Crafts and Gardens (Humberside) Limited | Wholesale & retail | 1975 |
| Crancher Holdings Limited | Financial services | 2026 |
| Cransbrook Ltd | Information & communication | 2026 |
| Cranswicks Land and Property Agents Limited | Real estate | 2025 |
| Crating Solutions UK Limited | Manufacturing | 2004 |
| Craven Fabrications Limited | Manufacturing | 2015 |
| Craven Fit-Out and Finishing Ltd | Construction | 2025 |
| Craven Projects Limited | Construction | 2013 |
| Cravings Delight Ltd | Hospitality | 2025 |
| CRE Hire Ltd | Hospitality | 2024 |
| Create Activate Ltd | Professional & scientific | 2012 |
| Create and Express Ltd | Information & communication | 2019 |
| Creatense Ltd | Wholesale & retail | 2025 |
| Creativ Limited | Professional & scientific | 1983 |
| Creative Infusions Music Education Ltd | Education | 2023 |
| Creative Interior Doors Limited | Professional & scientific | 2001 |
| Creative Landscapes(Hull) Ltd | Administrative & support | 2018 |
| Creative Projects Limited | Arts & recreation | 2006 |