| Cliffside Drive Management Company Limited | Households | 2017 |
| Cliftonville Glass Limited | Administrative & support | 2011 |
| Clinical Denture Centre Limited | Health & social care | 2012 |
| Clove Architects Ltd | Professional & scientific | 2021 |
| Club 100 International Limited | Arts & recreation | 2023 |
| Club 100 Racing Limited | Arts & recreation | 1999 |
| Coast Projects Ltd | Construction | 2019 |
| Coastal Construction S.E Ltd | Construction | 2024 |
| Coastal Data Systems Limited | Other services | 1995 |
| Coastal Life Limited | Wholesale & retail | 2026 |
| Coastal Plumbing and Heating Limited | Construction | 2025 |
| Coastal Property & Investment Company Limited(The) | Real estate | 1965 |
| Coastal Signs Limited | Professional & scientific | 2011 |
| Cockett Henderson Ltd | Real estate | 2010 |
| Code Carpentry Contractors Limited | Construction | 2014 |
| Coffee Corner Limited | Hospitality | 2010 |
| Cogent Heritage Consulting Ltd | Professional & scientific | 2019 |
| Coin-Op Consultants LLP | | 2011 |
| Colin Hills Developments Ltd | Construction | 2014 |
| Collingwood and Blake Court Residents Association Limited | Households | 1991 |
| Color ME Ltd | Other services | 2013 |
| Commonasmuckfilms Limited | Information & communication | 2023 |
| Community Window and Door Repairs Limited | Manufacturing | 2014 |
| Companies Trade & Shareholder Ltd | Information & communication | 2018 |
| Complete Construction Training Limited | Administrative & support | 2020 |
| Complete Safety Training Limited | Administrative & support | 2020 |
| Comprehensive Relational Counselling & Psychotherapy Limited | Health & social care | 2015 |
| Compton Computers Ltd | Other services | 2026 |
| Compton Hosting Ltd | Information & communication | 2026 |
| Compy Comps Ltd | Arts & recreation | 2025 |
| Conifer Sound Limited | Professional & scientific | 2025 |
| Connections Kent Ltd | Wholesale & retail | 2023 |
| Connor Endicott Services Limited | Construction | 2024 |
| Consult MCG Ltd | Real estate | 2018 |
| Coombersewell Enterprises LLP | | 2012 |
| Coombersewell Training CIC | Education | 2023 |
| Cooper Tarry Ltd | Extraterritorial | 2013 |
| Cooper Tarry Partners LLP | | 2013 |
| Copper Flame Consultancy Limited | Professional & scientific | 2026 |
| Copperhead Qara/Rp Services Ltd | Professional & scientific | 2022 |
| Copperleaf Maintenance Ltd | Real estate | 2020 |
| Copthorne Mews RTM Co Ltd | Households | 2024 |
| Coquinjambon Content Limited | Information & communication | 2021 |
| Corbetts Wharf Limited | Households | 1985 |
| Cordery Projects Limited | Professional & scientific | 2019 |
| Corner the Market Ltd | Professional & scientific | 2026 |
| Cornice Direct Limited | Manufacturing | 2015 |
| Cornwall Parker Limited | Information & communication | 2020 |
| Cosmyc Ltd | Health & social care | 2025 |
| Costain Care (Canterbury) Limited | Administrative & support | 2019 |
| Costain Care (Dover) Limited | Administrative & support | 2018 |
| Costain Care Holdings Limited | Financial services | 2018 |
| Costain Care Limited | Administrative & support | 2012 |
| Cox's Properties 43-45 Ltd | Households | 2024 |
| CPB Marine Limited | Professional & scientific | 2012 |
| CRA Property Services Ltd | Real estate | 2023 |
| Craftisan Ltd | Manufacturing | 2025 |
| Cranky Monkey Limited | Wholesale & retail | 2015 |
| Creative Jobs Creative People Limited | Administrative & support | 2025 |
| Creatp Limited | Professional & scientific | 2020 |
| Credo Group Ltd | Public administration | 2024 |
| Creeson Construction Limited | Other services | 2019 |
| Creesons Ltd | Construction | 2013 |
| Creesons Plumbing and Heating Ltd | Construction | 2024 |
| Crescent Peak Ltd | Financial services | 2025 |
| Creta Restaurant Ltd | Hospitality | 2022 |
| Cromon Ltd | Information & communication | 2015 |
| Cromon Music Ltd | Information & communication | 2023 |
| Cross Keys Learning Limited | Education | 2018 |
| Crossroads Property Limited | Real estate | 2023 |
| Crossworx Limited | Information & communication | 2023 |
| Crown Leisure Limited | Arts & recreation | 1976 |
| Crust Bakeries Ltd | Manufacturing | 2025 |
| Crusties Bakery Limited | Wholesale & retail | 2001 |
| Crusts Bakery Ltd | Wholesale & retail | 2023 |
| Csmithgb Ltd | Information & communication | 2014 |
| Cuba Properties Limited | Real estate | 2009 |
| Culture Compass Ltd | Professional & scientific | 2024 |
| Curve Roasters Ltd | Wholesale & retail | 2017 |
| Cuts Incorporated Limited | Other services | 2002 |
| CV Creative Limited | Administrative & support | 2018 |
| Cwdr Limited | Manufacturing | 2021 |
| CWU 1 Ltd | Real estate | 2026 |
| Cygnia Maintenance Limited | Administrative & support | 1994 |
| D a Horizons Limited | Information & communication | 2019 |
| D&A Water Hygiene Solutions Ltd | Water & waste | 2024 |
| D. Griffin Art & Design Ltd | Arts & recreation | 2021 |
| Daa's Thai Diner Ltd | Hospitality | 2003 |
| Daleep Investment Limited | Hospitality | 2018 |
| Damant MTA Limited | Health & social care | 2025 |
| DAN Cooper Garden Ltd | Wholesale & retail | 2021 |
| Daniel Hobbs Electrical Limited | Construction | 2021 |
| Dappyspinks Limited | Wholesale & retail | 2025 |
| Dasiho Ltd | Construction | 2019 |
| Datamad Limited | Information & communication | 2014 |
| Daughtrey & Sons Ltd | Real estate | 2023 |
| Dave Corp Ltd | Real estate | 2025 |
| Davelec Ltd | Construction | 2026 |
| David Bailey Furniture Systems Limited | Other services | 1982 |
| David DA Costa Limited | Wholesale & retail | 2011 |