| Connected in Nature CIC | Education | 2025 |
| Connected Wellness Ltd | Other services | 2024 |
| Connective (Edge) Groups Limited | Administrative & support | 2022 |
| Connock (London) Limited | Administrative & support | 2009 |
| Conor & Charles Services Ltd | Professional & scientific | 2025 |
| Conquad Consulting Limited | Professional & scientific | 2011 |
| Conquest Consulting Ltd | Professional & scientific | 2023 |
| Conscious Crafties Ltd | Wholesale & retail | 2021 |
| Conservation Grazing Management Ltd | Wholesale & retail | 2023 |
| Consilience Physiology Ltd | Professional & scientific | 2026 |
| Consilium BIO Limited | Professional & scientific | 2017 |
| Console Family Mediation Ltd | Professional & scientific | 2026 |
| Conspiriclear Ltd | Information & communication | 2025 |
| Constructing Siu-Lutions Ltd | Professional & scientific | 2025 |
| Construction and Management Solutions Ltd | Construction | 2024 |
| Construction Made Clear Ltd | Construction | 2023 |
| Consultema Limited | Health & social care | 2012 |
| Consumer Africa Limited | Information & communication | 2020 |
| Contact Roofing Limited | Construction | 2010 |
| Contain and Store Ltd | Transport & logistics | 2019 |
| Contalto Ltd | Professional & scientific | 2018 |
| Contemporary South Properties Ltd | Real estate | 2024 |
| Content Invent Limited | Information & communication | 1999 |
| Contentnexus Ltd | Information & communication | 2025 |
| Contilift Ltd | Manufacturing | 2023 |
| Continuum Debt Solutions Limited | Financial services | 2026 |
| Continuum Mechanics Ltd | Professional & scientific | 2025 |
| Control Visual Solutions Ltd | Construction | 2019 |
| Control Wise Solutions Ltd | Extraterritorial | 2023 |
| Converge Medical Ltd | Professional & scientific | 2020 |
| Conyers Place (Residents) Management Limited | Households | 1994 |
| Cookdom Ltd | Information & communication | 2022 |
| Cooke CJ Ltd | Wholesale & retail | 2022 |
| Cookie Barista (Bury) Ltd | Hospitality | 2023 |
| Cookies Aviation Services Limited | Manufacturing | 2020 |
| Cookmark Ltd | Information & communication | 2026 |
| Cool COW Crisps Limited | Manufacturing | 2025 |
| Cool Runnings Logistics Ltd | Administrative & support | 2021 |
| Cool-Tech Limited | Manufacturing | 2006 |
| Coolorca Ltd | Wholesale & retail | 2021 |
| Cooltraxx Ltd | Manufacturing | 2012 |
| Cooltraxx Outdoor Limited | Wholesale & retail | 2016 |
| Cooper Blue Limited | Professional & scientific | 2025 |
| Cooper Martin Holdings Mmxxvi Limited | Financial services | 2026 |
| Cooper's Garage Limited | Wholesale & retail | 2012 |
| Cooperfix Ltd | Construction | 2011 |
| Coopers Diamond Drilling Ltd | Construction | 2010 |
| Copa Development Ltd | Construction | 2018 |
| Copious Consultants Limited | Information & communication | 2019 |
| Cora Estates Ltd | Real estate | 2025 |
| Coralpanda Ltd | Wholesale & retail | 2023 |
| Corbex Ltd | Wholesale & retail | 2023 |
| Cordixa Ltd | Professional & scientific | 2018 |
| Core Construction and Landscapes Ltd | Administrative & support | 2023 |
| Corealia Timberframe Limited | Manufacturing | 2026 |
| Corelink Int’L Services Ltd | Wholesale & retail | 2025 |
| Corellian Consulting Limited | Information & communication | 2016 |
| Corelock Facilities Maintenance Ltd | Administrative & support | 2025 |
| Corelock Security Ltd | Administrative & support | 2025 |
| Coretec Engineering Limited | Professional & scientific | 2024 |
| Corner Family Limited | Wholesale & retail | 2022 |
| Corner of a Courtyard Limited | Information & communication | 2025 |
| Corner Shop TV Ltd | Information & communication | 2016 |
| Cornerstone Home Solution Ltd | Real estate | 2024 |
| Cornerwise Studio Ltd | Information & communication | 2026 |
| Cornwall Accessible Nature Parks CIC | Arts & recreation | 2026 |
| Cornwall Holmes Ltd | Professional & scientific | 2025 |
| Coro Management Limited | Wholesale & retail | 2012 |
| Coromandel Crafts Limited | Wholesale & retail | 1978 |
| Coronation Consult Limited | Information & communication | 2018 |
| Corotana Construction Limited | Construction | 2026 |
| Corotana Group Holdings Limited | Financial services | 2026 |
| Corporate Tiger Limited | Manufacturing | 2017 |
| Corporate Verve Ltd | Administrative & support | 2025 |
| Corrigan Electrical Contractors Limited | Construction | 2012 |
| Corserv Group Limited | Professional & scientific | 2013 |
| Corson & Co Limited | Administrative & support | 2026 |
| Cortex Education Ltd | Information & communication | 2026 |
| Cortex Health Consulting Ltd | Health & social care | 2025 |
| Corvya Global Ltd | Wholesale & retail | 2026 |
| Cosak Europe Ltd | Wholesale & retail | 2019 |
| Cosala Limited | Information & communication | 2021 |
| Cosier Towers Ltd | Real estate | 2023 |
| Cosmetic Competitions Ltd | Administrative & support | 2022 |
| Cosmetti Limited | Wholesale & retail | 2019 |
| Cosmic Digital Marketing Ltd | Administrative & support | 2020 |
| Cosmo Pet Products Ltd | Wholesale & retail | 2025 |
| Cosmos Cards Ltd | Wholesale & retail | 2024 |
| Cospce Ltd | Construction | 2025 |
| Cosphina Ltd | Wholesale & retail | 2026 |
| Costanzo Enrico Limited | Wholesale & retail | 2015 |
| Costmasterbuilder Ltd | Professional & scientific | 2024 |
| Cosy Services Ltd | Wholesale & retail | 2018 |
| Cosynest Property Limited | Real estate | 2024 |
| Cotswood Ltd | Construction | 2011 |
| Cottage Interiors Ltd | Wholesale & retail | 2022 |
| Could Run Should Run Ltd | Arts & recreation | 2026 |
| Coulson Logic Limited | Information & communication | 2022 |
| Coulter Travel Ltd | Administrative & support | 2020 |
| Count of Conamara Ltd | Arts & recreation | 2025 |