| Codelanguage Ltd | Information & communication | 2024 |
| Codemaven Limited | Administrative & support | 2015 |
| Coding LAB Life Ltd | Information & communication | 2021 |
| Coffee Mill Kitchen Limited | Hospitality | 2020 |
| Coffee ZIE Limited | Hospitality | 2025 |
| COL Investments Limited | Real estate | 2024 |
| Colby Limited | Professional & scientific | 2015 |
| Colemans Podiatry Ltd. | Health & social care | 2010 |
| Colin Woodman Limited | Administrative & support | 2016 |
| Collective Roofing Ltd | Construction | 2025 |
| Collins Family Restaurant Ltd | Hospitality | 2022 |
| Collins Groundworks Services Limited | Construction | 2025 |
| Collins Rail Services Limited | Construction | 2016 |
| Colour Space Ltd | Information & communication | 2019 |
| Colvin Contracts Limited | Administrative & support | 2014 |
| Combat Fight Series Limited | Arts & recreation | 2019 |
| Comedy Boat Party Limited | Arts & recreation | 2019 |
| Commercial Houses Ltd | Real estate | 2026 |
| Commshare Ltd. | Financial services | 1998 |
| Community Regeneration and Resource Limited | Administrative & support | 2009 |
| Community Sport Academies CIC | Education | 2021 |
| Commworks Limited | Professional & scientific | 2013 |
| Complete Computer Solutions Limited | Administrative & support | 1998 |
| Complete Coverage Maintenance Ltd | Construction | 2026 |
| Complete RAW Ltd | Wholesale & retail | 2023 |
| Compton Court (Sussex) Limited | Construction | 2012 |
| Conceio Consulting Ltd | Wholesale & retail | 2011 |
| Concept 4 Football Limited | Arts & recreation | 2024 |
| Concept Australia Limited | Professional & scientific | 2013 |
| Concise Controls (UK) Limited | Professional & scientific | 2002 |
| Conference Resource Limited | Administrative & support | 2011 |
| Confetti Payments Limited | Financial services | 2025 |
| Connect 247 AI Ltd | Information & communication | 2026 |
| Connect 4 Motors Ltd | Wholesale & retail | 2025 |
| Connect MBS Limited | Professional & scientific | 2024 |
| Conneely Consulting Ltd | Professional & scientific | 2017 |
| Conquest Martial Arts Ltd. | Arts & recreation | 2017 |
| Conscious Mama Ltd | Wholesale & retail | 2020 |
| Considerate Leadership Associate Support Services Limited | Administrative & support | 2023 |
| Consortium Homes Limited | Real estate | 2016 |
| Construction Consultancy Kent Ltd | Construction | 2012 |
| Consummate Holdings Ltd | Health & social care | 2024 |
| Contrive Solutions Limited | Information & communication | 2015 |
| Contrive Solutions SPV Ltd | Real estate | 2019 |
| Controlled Energy Solutions Limited | Professional & scientific | 2011 |
| Contrust Holdings Ltd | Administrative & support | 2024 |
| Cool Air AC Limited | Construction | 2025 |
| Cool Breeze Climate Control Limited | Energy | 2017 |
| Cool Conditioning Limited | Construction | 2015 |
| Cool Space Services Limited | Construction | 2019 |
| Cooling London Limited | Construction | 2014 |
| Copley Cooling Limited | Construction | 2021 |
| Copus Engineering Limited | Administrative & support | 2010 |
| Corida Sands Holding Ltd | Real estate | 2017 |
| Corinthian Plumbing & Heating Ltd | Construction | 2019 |
| Coris U.K. Limited | Administrative & support | 1987 |
| Corner Cafe (London) Limited | Hospitality | 2024 |
| Cornerstone Planning and Management Limited | Professional & scientific | 2025 |
| Cornerstone Property Surveying Ltd | Professional & scientific | 2026 |
| Coronation Autolocks Ltd | Administrative & support | 2015 |
| Corporate Fight Night Limited | Administrative & support | 2022 |
| Correct Window Repairs Limited | Construction | 2016 |
| Cosmedica Life Sciences Ltd | Professional & scientific | 2024 |
| Cosmos Cloud Ltd | Information & communication | 2014 |
| Cossington Court Limited | Households | 1990 |
| Cost Assure Limited | Professional & scientific | 2018 |
| Cotress Ltd | Wholesale & retail | 2026 |
| Cotswolds Design and Development Limited | Construction | 2023 |
| Counter Studio Limited | Professional & scientific | 2018 |
| Courage Healthcare Solutions Ltd | Health & social care | 2019 |
| Court Events Limited | Administrative & support | 2022 |
| Court Three Graphic Design Consultants Limited | Professional & scientific | 2004 |
| Cousins Facilities Limited | Real estate | 2002 |
| Covenant of Peace | Other services | 2010 |
| Cowshed Collective Ltd | Information & communication | 2017 |
| Cowshed Collective Ventures Ltd | Professional & scientific | 2024 |
| Cowshed Creators Ltd | Information & communication | 2019 |
| Cozy Property Flooring Limited | Construction | 2025 |
| CP Technical Limited | Construction | 2025 |
| Cphr Limited | Construction | 2011 |
| Craig & Coleman LLP | | 2017 |
| Craig Welch Design Ltd | Administrative & support | 2009 |
| Cravings Catering Limited | Hospitality | 2021 |
| Crawford Financial Limited | Professional & scientific | 2019 |
| Cray Barbers Ltd | Other services | 2023 |
| Cray Cafe Limited | Hospitality | 2023 |
| Cray Wanderers Football Club Limited | Administrative & support | 2004 |
| Cray Wanderers Kent Youth League CIC | Administrative & support | 2024 |
| Cray Wanderers Youth Junior CIC | Administrative & support | 2022 |
| Cray Wanderers Youth Senior CIC | Administrative & support | 2022 |
| Craymanor Holdings Limited | Administrative & support | 2011 |
| Craymanor Properties Ltd | Real estate | 2010 |
| Crazy Chicken Limited | Professional & scientific | 2019 |
| Cream Cushion Development Limited | Real estate | 2022 |
| Create Graphics Limited | Information & communication | 2010 |
| Create Property Developments Ltd | Construction | 2021 |
| Creative AI Network C.I.C. | Information & communication | 2024 |
| Creative Fabric Interiors Limited | Arts & recreation | 2013 |
| Creative Poke Limited | Arts & recreation | 2019 |
| Creative Society CIC | Administrative & support | 2023 |