| Capital Refresh Homes Ltd | Construction | 2025 |
| Capital View Limited | Professional & scientific | 2017 |
| Caprice (Rotherham) Limited | Wholesale & retail | 1981 |
| Caprice Clothing (UK) Limited | Wholesale & retail | 2011 |
| Captain Nicolas Limited | Hospitality | 2018 |
| Captivating Creatures Ltd | Arts & recreation | 2020 |
| Captivating Landscapes Yorkshire Ltd | Administrative & support | 2024 |
| Car & Go 4 Wheels Ltd | Wholesale & retail | 2026 |
| Car Empire Mot&Service Centre Ltd | Wholesale & retail | 2025 |
| Car Empire Used Cars and Vans Ltd | Wholesale & retail | 2023 |
| Car Store Auto Centre Ltd | Wholesale & retail | 2026 |
| Carb Ltd | Transport & logistics | 2025 |
| Carbonenergies Ltd | Professional & scientific | 2024 |
| Cardtronics Holdings Limited | Administrative & support | 2016 |
| Cardtronics Management Services Limited | Administrative & support | 2020 |
| Cardwala Ltd | Arts & recreation | 2025 |
| Care 4U Care Limited | Health & social care | 2008 |
| Care Assistance Group Ltd | Health & social care | 2023 |
| Care Buddies Limited | Health & social care | 2019 |
| Care for Dignity Ltd | Health & social care | 2022 |
| Care Force Security Services Ltd | Administrative & support | 2026 |
| Care Fortress Consulting Limited | Professional & scientific | 2025 |
| CARE2CARE Personnel Ltd | Health & social care | 2016 |
| CARE365 Solutions Limited | Health & social care | 2017 |
| Careblocks UK Ltd | Administrative & support | 2024 |
| Carl Stahl ARC Ltd | Construction | 2026 |
| Carl Stocks Limited | Wholesale & retail | 2006 |
| Carlan Homes Limited | Construction | 2021 |
| Carlton Hydraulics Limited | Manufacturing | 1989 |
| Carlton Restaurant Ltd | Hospitality | 2025 |
| Carlton Road Ltd | Real estate | 2012 |
| Carly Wilson Estates Ltd | Real estate | 2021 |
| Carly Wilson Estates South Yorkshire Limited | Real estate | 2025 |
| Carnova Vehicle Solutions Ltd | Other services | 2024 |
| Caroc Limited | Health & social care | 2022 |
| Carole's Kitchen Worksop Limited | Hospitality | 2023 |
| Carolus Limited | Professional & scientific | 2019 |
| Carpe Diem Homes Ltd | Real estate | 2024 |
| Carpetmania Limited | Extraterritorial | 2001 |
| Carsforyou Ltd | Wholesale & retail | 2023 |
| Carsure of Rotherham Ltd | Wholesale & retail | 2018 |
| Carsure Repairs and Servicing Ltd | Wholesale & retail | 2020 |
| Carter TRO Design Limited | Information & communication | 2026 |
| Cartersscaffolding Ltd | Construction | 2025 |
| Cartlyst Ltd | Wholesale & retail | 2025 |
| Cartridge Rotherham Plus Ltd | Wholesale & retail | 2003 |
| Casagrande Holdings Ltd | Financial services | 2017 |
| Caspian Property Services Limited | Real estate | 2026 |
| Cass Electric Company Limited | Construction | 1986 |
| Cassidy Business Holdings Limited | Real estate | 2013 |
| Cassymbhele Ltd | Health & social care | 2023 |
| Casting Innovations Limited | Manufacturing | 2010 |
| Castings Technology Holdings Limited | Financial services | 2020 |
| Castings Technology International Limited | Manufacturing | 2013 |
| Castle Estates (Hallam) Limited | Households | 2002 |
| Castle Estates (Mansfield) Ltd | Real estate | 2019 |
| Castle Estates (South Yorkshire) Ltd | Real estate | 2013 |
| Casual Mart Ltd | Wholesale & retail | 2026 |
| Catalindbr Limited | Professional & scientific | 2019 |
| Catcliffe Garage (Rotherham) Limited | Wholesale & retail | 2015 |
| Catcliffe Tyres Limited | Wholesale & retail | 2020 |
| Catermax Ltd | Hospitality | 2019 |
| Catherine Barber Ltd | Education | 2022 |
| Catherine Kavanagh Ltd | Other services | 2021 |
| Catm Europe Holdings Limited | Administrative & support | 2016 |
| Caughtyard Limited | Hospitality | 2014 |
| Cavaion Baumann UK Limited | Wholesale & retail | 2015 |
| Cavendish Properties (SY) Ltd | Real estate | 2025 |
| Caventra Group Ltd | Wholesale & retail | 2025 |
| CB Fabrications Limited | Professional & scientific | 2006 |
| CB Joinery and Maintenance Limited | Manufacturing | 2026 |
| CB Plumbing & Mechanical Services Limited | Construction | 2022 |
| CB Plumbing and Hvac Services Ltd | Construction | 2026 |
| CB Transport Services U.K. Ltd | Transport & logistics | 2019 |
| CBS Waste OIL Limited | Administrative & support | 2018 |
| CC2 Properties Ltd | Real estate | 2025 |
| Ccmtec Ltd | Other services | 2020 |
| CCS Homes Ltd | Real estate | 2024 |
| CCS Investments Limited | Financial services | 2021 |
| Cctv Hire & Sales Limited | Administrative & support | 2014 |
| CD Stainless Ltd | Wholesale & retail | 2014 |
| CDC Sales & Marketing Ltd | Administrative & support | 2013 |
| CDM Customs Ltd | Professional & scientific | 2025 |
| CDO Construction Ltd | Construction | 2026 |
| CE Drywall & Developments Ltd | Construction | 2026 |
| CEE Productions Limited | Information & communication | 2007 |
| CEG Trade Solutions Limited | Wholesale & retail | 2024 |
| Ceic Ltd | Construction | 2018 |
| Celestial Church of Christ - North East Province Limited | Other services | 2024 |
| Celestial Church of Christ Holy Spirit Parish | Other services | 2019 |
| Celik Fish Ltd | Hospitality | 2023 |
| Celtic Dawn Ltd | Real estate | 2024 |
| Celtic Driver Training Limited | Education | 2007 |
| Celtic Holdings Limited | Real estate | 2007 |
| Celtic Ocean Limited | Real estate | 1996 |
| Celtic Properties Investments Ltd | Real estate | 2009 |
| Celtic Property Lettings Limited | Real estate | 2024 |
| Celtic Torque Ltd | Real estate | 2001 |
| Central Advisors Ltd | Professional & scientific | 2019 |
| Central Dales Limited | Professional & scientific | 2017 |