| Chatsworth Court Ltd | Households | 2022 |
| Chatsworth Gardens (Eastbourne) Management Limited | Households | 2013 |
| Chcs CLG | Professional & scientific | 2015 |
| Cheap Web Ltd | Information & communication | 2023 |
| Chesspoint Limited | Professional & scientific | 2007 |
| Chichester Stone Creations Ltd | Wholesale & retail | 2022 |
| Chilli Graphics Limited | Manufacturing | 2001 |
| Chilli Pickle (South East) Limited | Hospitality | 2026 |
| Chilton Consultants Limited | Professional & scientific | 2013 |
| Chimer Ltd | Information & communication | 2026 |
| Chisholm Landscape Contractors Ltd | Administrative & support | 2021 |
| Chris Butler Archaeological Services Ltd | Professional & scientific | 2010 |
| Christian Burton Developments Ltd | Real estate | 2022 |
| Christian Burton Ltd | Real estate | 2015 |
| Chuckys Limited | Hospitality | 2023 |
| Citrus Conveyancing Limited | Professional & scientific | 2014 |
| Citygym Express Limited | Health & social care | 2009 |
| Cityskyline Developments Limited | Real estate | 2020 |
| Cjgc Limited | Information & communication | 2020 |
| CJP Build Ltd | Construction | 2022 |
| CJS Artificial Grass and Landscaping Ltd | Administrative & support | 2025 |
| Claire Boorman Coaching and Consulting Ltd | Other services | 2026 |
| Clarion Surveyors Ltd | Professional & scientific | 2013 |
| Clark & Webber Ltd | Construction | 2016 |
| Clavis Consulting Ltd | Professional & scientific | 2013 |
| Clean Energy Works Ltd | Professional & scientific | 2025 |
| Clear Counselling Ltd | Health & social care | 2025 |
| Clearkey Media Limited | Information & communication | 2021 |
| Clearwater Safety Group Ltd | Professional & scientific | 2011 |
| Clifton House (Eastbourne) Residents Association Limited | Other services | 1976 |
| Clindata Limited | Wholesale & retail | 2010 |
| Clive Court Property Limited | Households | 1995 |
| Coaching Supervision Academy Ltd | Education | 2008 |
| Coastal Plastering Contractors Limited | Construction | 2018 |
| Coastaways Ltd | Real estate | 2025 |
| Coastview Windows Ltd | Construction | 2025 |
| Coastways Ltd | Real estate | 2025 |
| Cobble Sussex Ltd | Manufacturing | 2026 |
| Cocoa and Coffee International Ltd | Manufacturing | 2025 |
| COE Construction Ltd | Construction | 2021 |
| Coldshield Properties Ltd | Construction | 2014 |
| Coldshield Window Systems Limited | Construction | 1996 |
| Coleman Plant Hire Ltd | Administrative & support | 2015 |
| Coleman Salmon Developments Ltd | Construction | 2022 |
| Colin Post Motor Engineers Ltd | Wholesale & retail | 2019 |
| Collantine Media Ltd | Arts & recreation | 2018 |
| Common Signal Ltd | Information & communication | 2025 |
| Community Action East Sussex | Other services | 2003 |
| Complete Mechanical Services Co. Limited | Construction | 1996 |
| COMPUTER2CLOUD Ltd | Information & communication | 2014 |
| Computerstyle Systems Ltd | Information & communication | 2014 |
| Comtech Internet Solutions Ltd | Information & communication | 2014 |
| Conan Limited | Transport & logistics | 2026 |
| Connective Family Ltd | Health & social care | 2017 |
| Conscious Creations Consultancy Limited | Professional & scientific | 2022 |
| Construction Experts Group Limited | Other services | 2017 |
| Consulting KH Ltd | Manufacturing | 2022 |
| Contour Carpets Limited | Wholesale & retail | 2003 |
| Copernicus and Wolf Acquisitions Ltd | Real estate | 2025 |
| Copernicus and Wolf Ltd | Construction | 2025 |
| Copper Bridge Music LLP | | 2021 |
| Copsource Ltd | Wholesale & retail | 2020 |
| Core Surveys Limited | Professional & scientific | 2004 |
| Corincraft Limited | Manufacturing | 1999 |
| Cornerstone Building Contractors Limited | Construction | 2010 |
| Cornford Crescent Management Company Ltd | Households | 2016 |
| Corsair Creative LLP | | 2013 |
| Court Lodge (Management) Limited | Households | 1999 |
| Crafty Bird Ltd | Professional & scientific | 2024 |
| Craftyannies Home CIC | Arts & recreation | 2019 |
| Creative Education Limited | Education | 2003 |
| Creative Kitchens & Building Services Ltd | Construction | 2021 |
| Creative Solutions & Consultancy Limited | Information & communication | 2002 |
| Crescent Dental Laboratory Ltd | Manufacturing | 2022 |
| Crestshield Windows Ltd | Construction | 2018 |
| Creu and Create Ltd | Manufacturing | 2023 |
| CRH Carpentry and Building Services Ltd | Construction | 2004 |
| Criptic Arts Productions CIC | Education | 2025 |
| Crorecruiter Ltd | Administrative & support | 2019 |
| Crowborough Mews Management Company Limited | Households | 1986 |
| Crowstone Engineering Ltd | Construction | 2014 |
| CRV Transport Services Ltd | Transport & logistics | 2019 |
| Crystal Infinity Ltd | Professional & scientific | 2012 |
| CT Eatery Ltd | Hospitality | 2019 |
| CT Property Maintenance Limited | Construction | 1998 |
| Cuckmere Community BUS Ltd | Transport & logistics | 2006 |
| Cuddle Plush Fabrics Limited | Wholesale & retail | 2019 |
| Curistica Ltd | Professional & scientific | 2023 |
| Curry Knight Limited | Hospitality | 2009 |
| CY Alcs Limited | Real estate | 2006 |
| Cypherlife Ltd | Information & communication | 2023 |
| D Brandon Limited | Wholesale & retail | 2004 |
| D H Driveways & Landscaping Limited | Administrative & support | 2023 |
| D P Goodwin Electrical Limited | Construction | 2022 |
| D P Goodwin Limited | Construction | 2018 |
| D Sutton Security Solutions Ltd | Administrative & support | 2014 |
| D. Bedford Properties Ltd | Households | 1996 |
| D.B. Domestic Appliances Limited | Wholesale & retail | 2003 |
| D.B. Domestics Holdings Limited | Professional & scientific | 2022 |
| Dakara Virtual Limited | Professional & scientific | 2015 |