| Computer Research Systems Limited | Information & communication | 1999 |
| Concept Design & Fabrication Limited | Manufacturing | 2017 |
| Concept First Limited | Information & communication | 2001 |
| Conceptual Innovations SW Ltd | Professional & scientific | 2014 |
| Concord House (Exeter) Limited | Real estate | 2024 |
| Concorde I Limited | Manufacturing | 1989 |
| Concorde II Limited | Extraterritorial | 2011 |
| Concorde III Limited | Extraterritorial | 2011 |
| Concorde Professional Services Limited | Extraterritorial | 2011 |
| Concrene Limited | Professional & scientific | 2018 |
| Coney Court Management Co. Ltd | Households | 2020 |
| Confirmed Carers Ltd | Information & communication | 2025 |
| Conform Concrete & Formwork Specialists Limited | Construction | 2003 |
| Conibear Consulting Limited | Extraterritorial | 2021 |
| Connaught Baldwin Ltd | Wholesale & retail | 1975 |
| Connected Child Health Ltd | Health & social care | 2021 |
| Connecting 4 Business (South East) Ltd | Wholesale & retail | 2025 |
| Connecting 4 Business Ltd | Wholesale & retail | 2004 |
| Connexe Limited | Information & communication | 2024 |
| Connor Consulting Ltd | Professional & scientific | 2019 |
| Conquering Horizons Limited | Manufacturing | 2015 |
| Conqueror 74 Trading Limited | Financial services | 2017 |
| Consensus Care Ltd | Administrative & support | 2026 |
| Consilium Cxxi Facades Ltd | Wholesale & retail | 2022 |
| Consilium Cxxi Holdings Ltd | Wholesale & retail | 2019 |
| Consilium Cxxi Ltd | Wholesale & retail | 2016 |
| Constance and Grace Ltd | Wholesale & retail | 2022 |
| Constantine Brown Limited | Real estate | 2024 |
| Constructing Futures Devon Ltd | Construction | 2018 |
| Construction and Groundworks Ltd | Construction | 2023 |
| Construction by Belfield Ltd | Construction | 2024 |
| Construction Law Claims Ltd | Professional & scientific | 2016 |
| Construction Project Management (SW) Limited | Professional & scientific | 2010 |
| Consultant Hub Ltd | Professional & scientific | 2014 |
| Contact Lenses & Spectacles Limited | Wholesale & retail | 2020 |
| Contour Landscaping & Design Ltd | Administrative & support | 2026 |
| Contract Staffing Solutions Ltd | Administrative & support | 2026 |
| Conversion Magic Ltd | Information & communication | 2018 |
| Conveyall Ltd | Information & communication | 2021 |
| Convodis Ltd | Information & communication | 2024 |
| Coogeetech Limited | Information & communication | 2023 |
| Cookies N Dream Limited | Wholesale & retail | 2020 |
| Cookiewolf Co-Op Ltd | Information & communication | 2022 |
| Cooksleys Management (2001) Limited | Real estate | 2001 |
| Cooksleys Sales Ltd | Real estate | 2018 |
| Cool Blue Solutions Limited | Information & communication | 2024 |
| Cool Red Limited | Real estate | 2017 |
| Coolings Management Limited | Professional & scientific | 2007 |
| Coolth Limited | Construction | 2009 |
| Coombe Plumbing and Heating Limited | Construction | 2017 |
| Coomber Holdings Investments Limited | Other services | 2014 |
| Cooper Golding Limited | Other services | 2011 |
| Cooper Williamson Ltd | Real estate | 2025 |
| Cooperative AI Foundation | Professional & scientific | 2021 |
| Coote Concrete Structures Limited | Construction | 2015 |
| Copabet Crowd Limited | Financial services | 2025 |
| Copley Group Ltd | Information & communication | 2024 |
| Coporatelettingssw Ltd | Hospitality | 2024 |
| Coppa Properties Ltd | Real estate | 2024 |
| Copper Flower Films Ltd | Information & communication | 2019 |
| Copperfields (Alphington) Management Company Limited | Households | 1988 |
| Copping Construction & Carpentry Ltd | Manufacturing | 2019 |
| Copplestone Construction Limited | Construction | 2020 |
| Copse Hill Ltd | Agriculture & fishing | 2025 |
| COQ Group Ltd | Hospitality | 2025 |
| Coral Psychology Limited | Health & social care | 2019 |
| Corden Studios Ltd | Arts & recreation | 2021 |
| Core Bike Fit Ltd | Wholesale & retail | 2022 |
| Core Projects Limited | Construction | 2008 |
| Core Security Service Limited | Administrative & support | 2014 |
| Core Values Limited | Extraterritorial | 2009 |
| Coreus Central Ltd | Construction | 2021 |
| Coreus Developments Limited | Professional & scientific | 2019 |
| Coreus Financial Services Ltd | Professional & scientific | 2024 |
| Coreus Projects Limited | Construction | 2018 |
| Coreus South East Ltd | Construction | 2021 |
| Coreus South West Ltd | Construction | 2021 |
| Coreus Sustainability Ltd | Construction | 2021 |
| Coreus Uk&I Limited | Construction | 2025 |
| Corigan Ltd | Information & communication | 2021 |
| Corinto Limited | Professional & scientific | 2008 |
| Corkscrew Ltd | Education | 2010 |
| Cornell Construction Ltd. | Construction | 2008 |
| Cornerstone Academy Trust | Education | 2010 |
| Cornish Garlic Co Ltd | Agriculture & fishing | 2024 |
| Cornish Inns Limited | Hospitality | 2019 |
| Cornish Rock Tors Limited | Arts & recreation | 2006 |
| Cornstead Ltd | Extraterritorial | 2024 |
| Cornwall Containers Ltd | Transport & logistics | 2018 |
| Cornwall Design Engineering Consultants Ltd | Construction | 2009 |
| Cornwall Event Hire Solutions Ltd | Administrative & support | 2026 |
| Cornwall Tyre Ltd | Wholesale & retail | 2023 |
| Cornwallis Group Limited | Financial services | 2018 |
| Cornwallis Mackenzie (UK) Ltd | Professional & scientific | 2009 |
| Corso & Dean Limited | Real estate | 2025 |
| Corte Security Ltd | Administrative & support | 2022 |
| Cortex Tutors Ltd | Education | 2024 |
| Cosford Fitness Ltd | Health & social care | 2013 |
| Cosmetic Practitioner Register LP | | 2015 |
| Cosmetic Practitioner Training Academy LP | | 2015 |