| Callisto Medical Ltd | Health & social care | 2025 |
| Caltron Engineering Limited | Professional & scientific | 2023 |
| Caltron Properties Ltd | Construction | 2021 |
| Calvary Outreach Ministries Worldwide | Other services | 2002 |
| CAM Electrical Solutions Ltd | Construction | 2023 |
| Cambridge Computer Resources Ltd | Information & communication | 2013 |
| Camelcastle Limited | Real estate | 1979 |
| Camelot Kids Limited | Education | 2015 |
| Camex Project Ltd | Professional & scientific | 2016 |
| Camlock Group Limited | Financial services | 2009 |
| Camlock Systems Limited | Manufacturing | 1977 |
| Camlock.Com Limited | Professional & scientific | 2007 |
| Camryn IT Limited | Information & communication | 2014 |
| Candell Flat Management Limited | Households | 1999 |
| Cane Adam Limited | Wholesale & retail | 1985 |
| Canford Residents Management Limited | Households | 2007 |
| Canne Collective Ltd | Manufacturing | 2026 |
| Cantilever Group Limited | Information & communication | 2011 |
| Cantilever Media Limited | Information & communication | 2020 |
| Cantina Eastbourne Limited | Hospitality | 2024 |
| Canton Martial Arts Ltd | Education | 2021 |
| Canton Merchandise Ltd | Wholesale & retail | 2021 |
| Canvale Limited | Construction | 1992 |
| Capital Electric Wholesale Limited | Wholesale & retail | 2001 |
| Cappital Ventures Ltd | Financial services | 2025 |
| Car Body Panels Limited | Wholesale & retail | 2011 |
| CARDIV2013 Limited | Health & social care | 2013 |
| Care and Clean With a Difference Ltd | Administrative & support | 2022 |
| Care Direct Group Limited | Administrative & support | 2017 |
| Care for the Carers | Health & social care | 1998 |
| Care to YOU Healthcare 2 Limited | Extraterritorial | 2020 |
| Care to YOU Healthcare Limited | Health & social care | 2017 |
| Care+Eastsussex Ltd | Administrative & support | 2017 |
| CARE2U Recruitment Ltd | Administrative & support | 2019 |
| Carew Court (Eastbourne) Limited | Households | 1993 |
| Carfix Sussex Ltd | Wholesale & retail | 2020 |
| Caribou One Limited | Financial services | 2023 |
| Carify Ltd | Wholesale & retail | 2025 |
| Carlisle Grange Residents Company Limited | Households | 1983 |
| Carlisle Lodge Limited | Hospitality | 2010 |
| Carlos Fernandez Limited | Other services | 2012 |
| Carmenna Ltd | Health & social care | 2025 |
| Carmine Court Management Company Limited | Households | 2010 |
| Carmonzo Limited | Financial services | 2022 |
| Caroline Fooks Design Limited | Construction | 2009 |
| Carpers DEN Ltd | Wholesale & retail | 2024 |
| Carpurna Limited | Health & social care | 2020 |
| Carr Property (Eastbourne) Limited | Real estate | 2019 |
| Carr Property Maintenance & Management Services Limited | Real estate | 2016 |
| Carrington Place (Goodwin) Management Ltd | Households | 2013 |
| Carroll Industrial Holdings Limited | Financial services | 2017 |
| Carroll Investments Limited | Financial services | 2017 |
| Carsana Group Holdings Ltd | Financial services | 2026 |
| Carsite Ltd | Wholesale & retail | 2023 |
| Carsmart Sussex Limited | Administrative & support | 2019 |
| Carston Mart Ltd | Wholesale & retail | 2024 |
| Cartela International Ltd | Manufacturing | 2026 |
| Carter Project Management UK Ltd | Professional & scientific | 2018 |
| Carters Fish & Chips (Eastbourne) Limited | Hospitality | 2009 |
| Carters Plastering and Rendering Ltd | Construction | 2022 |
| Carthage Haulage Limited | Transport & logistics | 2014 |
| Casa DA Pier Limited | Hospitality | 2025 |
| Casa DE Monte Serrana Ltd | Construction | 2005 |
| Casa Libelula Limited | Professional & scientific | 2020 |
| Casa MEX Limited | Wholesale & retail | 2026 |
| Casacala Limited | Construction | 1996 |
| Cashen Real Estate Ltd | Real estate | 2021 |
| Cashflow Protector Limited | Administrative & support | 2005 |
| Caslean Limited | Professional & scientific | 2021 |
| Caslin Holdings Ltd | Financial services | 2019 |
| Caspian Capital Management Ltd | Financial services | 2025 |
| Cassidy Consulting Limited | Information & communication | 1995 |
| Casson Associates Limited | Professional & scientific | 2008 |
| Casson Consulting Ltd | Administrative & support | 2018 |
| Castle Garden Rooms Limited | Construction | 2020 |
| Castle Hygiene & Therapy Limited | Health & social care | 2023 |
| Castle Inn Hotel Bramber Ltd | Hospitality | 2025 |
| Castle Inn Pevensey Bay Limited | Hospitality | 2017 |
| Castle Road Dental Limited | Health & social care | 2025 |
| Castle Wells Estates Limited | Real estate | 2015 |
| Castlegal Estates Ltd | Real estate | 2022 |
| Cat a. Tonic Tattoos Ltd | Arts & recreation | 2024 |
| Catch UP Taxi Ltd | Transport & logistics | 2019 |
| Catchbadge Ltd | Manufacturing | 2026 |
| Cater London Ltd | Hospitality | 2014 |
| Catering Eastbourne Ltd | Hospitality | 2020 |
| Caterserv Ltd | Manufacturing | 2018 |
| Cathead Limited | Construction | 2021 |
| Cathy Healthcare Ltd | Public administration | 2018 |
| Catlaytic Investment Group Limited | Professional & scientific | 2021 |
| Catt Collective Ltd | Real estate | 2025 |
| Catt Construction Ltd | Construction | 2024 |
| Cavendish Apartments Ltd | Real estate | 2014 |
| Cavendish Court Eastbourne Limited | Households | 1999 |
| Cavendish Education Trust | Education | 2012 |
| Cavendish House Properties Ltd | Construction | 2023 |
| Cavendish Place (Eastbourne) Limited | Manufacturing | 2001 |
| Cavendish Place Residents Management Limited | Households | 2024 |
| Cayman Court Management Limited | Households | 1983 |
| Cazscleaning Ltd | Administrative & support | 2025 |