| CB Wright Software Solutions Ltd | Information & communication | 2012 |
| Ccat Properties Limited | Real estate | 2023 |
| CE Construction and Development Ltd | Construction | 2025 |
| Cedar Way Change Consultancy LLP | | 2026 |
| Cedarberg Travel Ltd | Administrative & support | 1994 |
| Century Workwear Limited | Wholesale & retail | 2000 |
| Ceoc (UK) Limited | Administrative & support | 2009 |
| Cerve Limited | Manufacturing | 2007 |
| Cervus Creative Holdings Ltd | Financial services | 2025 |
| Chailey Bonfire Society Limited | Administrative & support | 1999 |
| Chailey Common Residents Management Company Limited | Households | 2007 |
| Chailey Heritage Foundation | Education | 1999 |
| Chailey Heritage Trading Company Limited | Hospitality | 2016 |
| Chailey Plumbers Ltd | Construction | 2025 |
| Chalk Gallery Ltd | Arts & recreation | 2005 |
| Chalkham Maintainance Ltd | Real estate | 2024 |
| Chalkham Management Limited | Agriculture & fishing | 2021 |
| Chalkham Properties Limited | Real estate | 2022 |
| Chalkwood Holdings Ltd | Real estate | 2018 |
| Chamberlain Dunn Associates Limited | Information & communication | 1995 |
| Chapel Hill Property Ltd | Real estate | 2019 |
| Chapman and SON Building Development Ltd. | Construction | 2015 |
| Chardec Limited | Manufacturing | 2019 |
| Charles Wycherley Independent Estate Agents Limited | Real estate | 2022 |
| Charleston Enterprises Limited | Wholesale & retail | 1987 |
| Charleston Lewes Limited | Arts & recreation | 2022 |
| Charliemonro Ltd | Real estate | 2024 |
| Charteris Ltd | Professional & scientific | 2026 |
| Chat & EAT (Lewes) Ltd | Hospitality | 2025 |
| Chaterfields Limited | Hospitality | 2022 |
| Chaulas Limited | Hospitality | 2003 |
| Check Left Ltd | Information & communication | 2016 |
| Cheese Please Limited | Wholesale & retail | 2020 |
| Chelverton Investments UK Ltd | Hospitality | 2023 |
| Cherry Tree Training Management Ltd | Administrative & support | 2015 |
| Chiddingly Camp and Caravan Park Limited | Hospitality | 2021 |
| Chiddingly Storage Ltd | Real estate | 2016 |
| China-Europe Investment Group Ltd | Information & communication | 2024 |
| Chipworks Data Ltd | Administrative & support | 2017 |
| Choice Help Care Ltd | Health & social care | 2026 |
| Choose Ltd | Information & communication | 2005 |
| Chownes L.P. | | 2009 |
| Chris Dowling Limited | Construction | 2013 |
| Chrismas & Company Solicitors Limited | Professional & scientific | 2012 |
| Christ Victory Life Chapel | Other services | 2023 |
| Chrysalis Research UK Limited | Professional & scientific | 2010 |
| Chufty Lights Limited | Arts & recreation | 2024 |
| Church Electricians Limited | Construction | 2017 |
| Church Hill Antiques Centre Limited | Real estate | 2005 |
| Church Lane 2025 Limited | Real estate | 2025 |
| Church Road Advisory Limited | Financial services | 2015 |
| Cinderfield Consulting Ltd | Professional & scientific | 2014 |
| Circle of Life Rediscovery Community Interest Company | Education | 2007 |
| CJ Consulting & Creative Services Ltd | Information & communication | 2019 |
| CJL Creative Ltd | Information & communication | 2019 |
| Clarence House Freehold Limited | Households | 2004 |
| Clark Brownscombe Limited | Professional & scientific | 2014 |
| Clarks Design & Build Ltd | Construction | 2013 |
| Clavecins Sans Frontières Ltd | Manufacturing | 2024 |
| Clayhill Co-Housing Ltd | Real estate | 2023 |
| Clear Creations Ltd | Administrative & support | 2008 |
| Clear Retirement Ltd | Financial services | 2018 |
| Clear Sky Sustainable Homes Ltd | Professional & scientific | 2009 |
| Clear View Creative Limited | Information & communication | 1998 |
| Clever Solutions (Inc) Ltd | Professional & scientific | 2022 |
| Cliffe Accountants Ltd | Professional & scientific | 2023 |
| Cliffe Bonfire Limited | Other services | 2008 |
| CLIFFE33 Ltd | Real estate | 2019 |
| Clothsmith Ltd | Information & communication | 2019 |
| Cloud-Hidden Ltd. | Information & communication | 2013 |
| Clswift Ltd | Health & social care | 2024 |
| Club Amigos Ltd | Education | 2013 |
| Cluniac Network-Education and Involvement Community Interest Company | Education | 2024 |
| Cmcf Medical Limited | Health & social care | 2024 |
| CMS Coachworks Limited | Wholesale & retail | 2010 |
| Co-Ax Valves UK Ltd | Wholesale & retail | 2017 |
| Co-Ecology Limited | Professional & scientific | 2021 |
| Co-Innovate Learning Ltd | Information & communication | 2020 |
| Coaasi Holdings Ltd | Real estate | 2018 |
| Coachcreates Ltd | Professional & scientific | 2014 |
| Coast to Coast Consultancy Limited | Professional & scientific | 2024 |
| Coastal Estate Management Ltd. | Real estate | 1987 |
| Coastal Residential Management Limited | Real estate | 1998 |
| Coastal Wellbeing Limited | Health & social care | 2013 |
| Coastline Fire Alarms Limited | Public administration | 2019 |
| Coastline Fire Protection Limited | Public administration | 2008 |
| Colin Dartnell Properties Limited | Real estate | 2001 |
| Collins Roofline Ltd | Construction | 2025 |
| Colour Makes People Happy Limited | Wholesale & retail | 2018 |
| Comber of Lewes & Co Ltd | Wholesale & retail | 2023 |
| Comedy Plaza Ltd | Information & communication | 2025 |
| Commercial Square Bonfire Limited | Other services | 2014 |
| Common Cause Co-Operative Limited | Agriculture & fishing | 1994 |
| Common Interest CIC | Financial services | 2018 |
| Community Chef - Good Food for ALL C.I.C. | Hospitality | 2013 |
| Community Energy Pathways C.I.C. | Professional & scientific | 2018 |
| Company of Things London Ltd | Professional & scientific | 2023 |
| Compass Trailers Ltd | Manufacturing | 2011 |
| Complete Fictions Limited | Arts & recreation | 2006 |
| Complete Landscape Garden Services Limited | Arts & recreation | 1995 |