| Carters of Suffolk at Stonham Barns Ltd | Wholesale & retail | 2019 |
| Cassiope Commerce Limited | Other services | 2018 |
| Castle Golf School Limited | Professional & scientific | 2012 |
| Castle Hill Consultants Limited | Professional & scientific | 2011 |
| Castle Leisure Parks Ltd | Hospitality | 2024 |
| Cavendish Osteopaths Limited | Health & social care | 2017 |
| CBS International Property Limited | Other services | 2013 |
| CD Improvements Ltd | Professional & scientific | 2020 |
| CDB Marketing Limited | Professional & scientific | 2018 |
| CEC Developments Limited | Construction | 2016 |
| CEC Electrical Specialists Limited | Construction | 2011 |
| Ceris Burns International Limited | Professional & scientific | 2010 |
| Cesspit Replacement Ltd | Construction | 2026 |
| Chadwick Park Limited | Construction | 1993 |
| Chantler & SON Roofing Ltd | Construction | 2022 |
| Chapels Cafe Ltd | Hospitality | 2022 |
| Charterhouse Sky Developments Limited | Construction | 2016 |
| Chaser Pest Control Limited | Administrative & support | 2016 |
| Chater Food and Drink Ltd | Hospitality | 2025 |
| Chaucer Property Developments Limited | Real estate | 2002 |
| Chelsea Educational Ltd | Education | 2014 |
| Cherry Garth Property Limited | Hospitality | 2018 |
| Cheviot Installations Limited | Construction | 2017 |
| Chiltern Parks Ltd | Real estate | 2018 |
| Christian Communications Partnership Limited | Information & communication | 1997 |
| Chrome Cast (UK) Limited | Health & social care | 2014 |
| Churchill (1945) Ltd | Financial services | 2019 |
| Churchill Park Homes Ltd | Real estate | 2017 |
| CHW International Limited | Wholesale & retail | 2025 |
| Cinematic Collective Limited | Information & communication | 2017 |
| Citadel NY UK Company Ltd | Wholesale & retail | 2015 |
| Claire Johnson Creative Limited | Professional & scientific | 2019 |
| Claire Nash Solicitors Limited | Professional & scientific | 2017 |
| Clarke & Drury Ltd | Construction | 2015 |
| Clarke's SME Consulting Ltd | Professional & scientific | 2023 |
| Clarks Catering Ltd | Wholesale & retail | 2024 |
| Clegg & Co. Ltd | Hospitality | 2025 |
| Clever Squirrel Ltd | Professional & scientific | 2025 |
| Climergy Ltd | Construction | 2022 |
| Clive Roberts Limited | Construction | 1988 |
| Clock Care Limited | Other services | 2004 |
| CNJ an Sons Limited | Wholesale & retail | 2023 |
| Co Barns Limited | Construction | 2015 |
| Coachedbyhattie Ltd | Health & social care | 2025 |
| Cobble Mcpsh Limited | Professional & scientific | 2021 |
| Codefact Limited | Information & communication | 2023 |
| Codsems Limited | Professional & scientific | 2019 |
| Cognaitive Limited | Information & communication | 2025 |
| Cognatech Ltd | Information & communication | 2006 |
| Colonial Investments Limited | Extraterritorial | 2014 |
| Community Hospitals Association | Health & social care | 2013 |
| Compatibility Limited | Wholesale & retail | 1985 |
| Complete Commissioning Solutions LLP | | 2008 |
| Composite Interiors (South East) Co. Limited | Construction | 2000 |
| Composite Interiors Limited | Construction | 2016 |
| Concrete Corrosion Limited | Construction | 2006 |
| Condor Brickwork Ltd | Construction | 2025 |
| Connect Vision International Limited | Administrative & support | 2020 |
| Connections Services Limited | Professional & scientific | 2016 |
| Conscious Collision Limited | Hospitality | 2020 |
| Conscious Landscape LLP | | 2022 |
| Conservative Friends of Australia Limited | Other services | 2019 |
| Consult Secure Limited | Construction | 2019 |
| Context Agency UK Ltd | Professional & scientific | 2026 |
| Coombe Mill Properties Limited | Real estate | 1999 |
| Coppice Wood Residents Company Limited | Households | 2011 |
| Corcoran and MAY (Sevenoaks) Limited | Wholesale & retail | 2008 |
| Cosee Ltd | Administrative & support | 2022 |
| Countrywide Corporate Consultants Limited | Real estate | 2005 |
| Courtwell (Crowborough) Management Limited | Real estate | 2006 |
| Cowen Techworks Ltd | Information & communication | 2023 |
| CR Bastin Ltd | Construction | 2025 |
| Crabtree Property Ltd | Real estate | 2024 |
| Crane Designs Limited | Information & communication | 2015 |
| Cransford Limited | Manufacturing | 1991 |
| Creation Landscapes Ltd | Construction | 2019 |
| Creators United Management Ltd | Professional & scientific | 2025 |
| Crescent Holdings Group Limited | Construction | 2021 |
| CRG Publications Plus Ltd | Other services | 2006 |
| Cristal Holdings Ltd | Other services | 2024 |
| Cross Stone (Parq) Limited | Construction | 2014 |
| Cross Stone Estates Limited | Construction | 2014 |
| Cross Stone Holdings Limited | Financial services | 2023 |
| Cross Stone Homes Limited | Construction | 1993 |
| Cross Stone Properties Limited | Construction | 1985 |
| Cross Stone Regeneration (Shoreham) Limited | Construction | 2018 |
| Cross Stone Regeneration Limited | Financial services | 2015 |
| Cross Stone Securities Limited | Construction | 2001 |
| Crowborough Bonfire and Carnival Society Limited | Other services | 1997 |
| Crowborough Community Hub C.I.C. | Other services | 2024 |
| Crowborough Community Pantry C.I.C. | Hospitality | 2024 |
| Crowborough Court Management (East Sussex) Limited | Real estate | 2003 |
| Crowborough Crystal Car Wash Ltd | Wholesale & retail | 2023 |
| Crowborough Drive Management Company Limited | Households | 2012 |
| Crowborough DRY Cleaners Ltd | Other services | 2016 |
| Crowborough Executive Private Hire Ltd | Transport & logistics | 2023 |
| Crowborough Fitness Company Ltd | Other services | 2022 |
| Crowborough for Young People Ltd | Information & communication | 2001 |
| Crowborough Glassworks Ltd. | Manufacturing | 1993 |
| Crowborough Hospitality Ltd | Hospitality | 2017 |