| CBT Bike Training Ltd | Education | 2023 |
| CD Real Estate LLP | | 2025 |
| Cdms (Sussex) Limited | Administrative & support | 2007 |
| Cedena Ltd | Construction | 2024 |
| Ceen Ltd | Professional & scientific | 2020 |
| Cellar Technician Limited | Professional & scientific | 2026 |
| Centre of Aviation Photography Ltd | Professional & scientific | 2015 |
| Centred Excellence Limited | Education | 2010 |
| Certitude Limited | Administrative & support | 2019 |
| CFL Property Limited | Real estate | 2024 |
| CG Newsagents Ltd | Wholesale & retail | 2019 |
| CG Spark Limited | Health & social care | 2024 |
| Chaise Property Ltd | Real estate | 2022 |
| Chalet Girl Films Distribution Ltd | Information & communication | 2010 |
| Chalet Sorbier Limited | Real estate | 1997 |
| Chalk & Flint Estates Ltd | Real estate | 2026 |
| Chalvington Barns Commercial Ltd | Construction | 2021 |
| Chalvington Barns Construction Ltd | Construction | 2016 |
| Champney Equestrian Limited | Agriculture & fishing | 2014 |
| Chapter Twenty Ltd | Financial services | 2015 |
| Charity Gift Vouchers Marketing Ltd. | Wholesale & retail | 1999 |
| Cheery Bear LLP | | 2019 |
| Chelsey Mason Limited | Health & social care | 2024 |
| Chester Developments (Sussex) Limited | Extraterritorial | 2001 |
| Chiddfest Limited | Arts & recreation | 2018 |
| Chill Leisure Ltd | Hospitality | 2019 |
| Chiltern Imaging Partnership LLP | | 2022 |
| Chlorella World Limited | Wholesale & retail | 2008 |
| Chocolate International Limited | Wholesale & retail | 2019 |
| Choix Limited | Wholesale & retail | 2023 |
| CHR Developments Group Ltd | Construction | 2024 |
| Chris Tullett Ltd | Construction | 2023 |
| Chronos Management Ltd | Information & communication | 2022 |
| Ciccarino Management Ltd | Hospitality | 2024 |
| Cinderella's Prom Limited | Wholesale & retail | 2014 |
| Circle Forestry Ltd | Professional & scientific | 2014 |
| Citadel Magna Capital Ltd | Professional & scientific | 2013 |
| CJC Wealth Management Ltd | Information & communication | 2015 |
| CJE Consultancy Ltd | Professional & scientific | 2022 |
| CJS Residential Ltd | Real estate | 2019 |
| Claire Ganly Design Limited | Administrative & support | 2020 |
| Clapwater Farm LLP | | 2014 |
| Claremont Development Group Limited | Construction | 2024 |
| Clarendon Equestrian Limited | Manufacturing | 1979 |
| Clarke Developments (Sussex) Limited | Construction | 2015 |
| Clarke Family Developments LLP | | 2011 |
| Clarke Golf Limited | Professional & scientific | 2022 |
| Clarke Interim Management Limited | Professional & scientific | 2013 |
| Clarke Roofing (Holdings) Limited | Professional & scientific | 2000 |
| Clarke Roofing and Construction (South East) Limited | Construction | 2013 |
| Clark’S Carpentry Limited | Manufacturing | 2025 |
| Classic Joinery (Sussex) Limited | Manufacturing | 2002 |
| Classic Oak Framing Ltd | Construction | 2006 |
| Claudia Rosa Ltd | Extraterritorial | 2012 |
| Clear Surveys Ltd | Professional & scientific | 2018 |
| Clements & Harris Land and Development Limited | Construction | 2016 |
| Clements & Harris Limited | Construction | 2010 |
| Clements and Harris Property and Lettings Limited | Real estate | 2017 |
| Clever Therapy Sites Limited | Information & communication | 2024 |
| Clifton Court RTM Company Ltd | Households | 2023 |
| Clitheroe Estates Limited | Real estate | 2017 |
| CLL Ltd | Administrative & support | 2018 |
| Clockwork Exhibitions Limited | Administrative & support | 1996 |
| Clockwork Powder Coating Limited | Manufacturing | 2003 |
| Cloud Nine PR and Marketing Limited | Administrative & support | 2012 |
| Cloudrpo (Group) Limited | Information & communication | 2009 |
| Clover Design and Build Ltd | Construction | 2023 |
| Cloyes Estates Limited | Construction | 1998 |
| CM & NM Properties Ltd | Real estate | 2024 |
| CME Surveying Limited | Professional & scientific | 2017 |
| CMG Physio Limited | Other services | 2012 |
| CMS Citroen Specialists Ltd | Wholesale & retail | 2018 |
| CNC Inspire Ltd | Manufacturing | 2021 |
| Cnep Management Limited | Real estate | 2013 |
| Coach Academy Ltd | Wholesale & retail | 2023 |
| Coap Media Ltd | Professional & scientific | 2025 |
| Coap Online Ltd | Other services | 2021 |
| Coap Wings Limited | Professional & scientific | 2024 |
| Coast Environmental Limited | Water & waste | 2024 |
| Coastal Catering Services Limited | Hospitality | 2024 |
| Coastal Property Holdings Ltd | Real estate | 2023 |
| Coastal Steel Fabrications Limited | Manufacturing | 2025 |
| Cobie Vetcare Limited | Extraterritorial | 2015 |
| Coda Healthcare Communications Limited | Professional & scientific | 2015 |
| Codazep Ltd | Arts & recreation | 2023 |
| Cogen Consulting Ltd | Extraterritorial | 2013 |
| Colbran and Wingrove Ltd | Construction | 1995 |
| Cold Fusion Glass Arts & Gifts @Themalthouse Ltd | Education | 2015 |
| Coldham Field Ltd | Professional & scientific | 2003 |
| Coldharbour Business Park LLP | | 2020 |
| Collection 9 Design Limited | Professional & scientific | 2026 |
| Collina Limited | Construction | 2002 |
| Collins Electrical Management Services Limited | Professional & scientific | 2014 |
| Collins Green Limited | Construction | 2006 |
| Colonial Rock Limited | Financial services | 2016 |
| Colour Wheel Eastbourne Ltd | Education | 2026 |
| Colourpro Ltd | Construction | 2016 |
| Comfi Space Ltd | Construction | 2020 |
| Comics and Beyond Ltd | Wholesale & retail | 2022 |
| Command Concepts (UK) Ltd | Education | 2018 |