| Combined Development Group Ltd | Construction | 2019 |
| Combined Project One Limited | Construction | 2019 |
| Come Round Ltd | Administrative & support | 2010 |
| Comfort Box Property Ltd | Real estate | 2022 |
| Comic Games Limited | Arts & recreation | 2024 |
| Comindex SA Ltd | Information & communication | 2026 |
| Commercial Door Services Limited | Construction | 2004 |
| Commercial Enterprise Lettings Limited | Financial services | 2024 |
| Commercial GAS Catering Limited | Manufacturing | 2013 |
| Commercial Heating & Drying Holdings Limited | Financial services | 2020 |
| Commercial Heating & Drying Limited | Other services | 2020 |
| Commercial Kitchen Technicians Limited | Wholesale & retail | 2025 |
| Commercial Property Finders Ltd | Professional & scientific | 2024 |
| Commercial Van Seating Limited | Wholesale & retail | 2016 |
| Commercial Vehicle Specialists Limited | Manufacturing | 2015 |
| Commercialandbridging Limited | Financial services | 2012 |
| Commkleen Ltd | Administrative & support | 2010 |
| Common Farm Motocross Ltd | Arts & recreation | 2024 |
| Commonwealth Ltd | Real estate | 2011 |
| Communicado Consulting Ltd | Wholesale & retail | 2026 |
| Community Practitioner Alliance C.I.C. | Health & social care | 2015 |
| Community Spirit (Doncaster) C.I.C | Other services | 2006 |
| Communityrx Ltd | Wholesale & retail | 2025 |
| Compagno Limited | Wholesale & retail | 2022 |
| Companion Homecare Doncaster Ltd | Health & social care | 2026 |
| Company C&V Ltd | Transport & logistics | 2020 |
| Company Creations & Control Limited | Professional & scientific | 1996 |
| Company Discount Limited | Professional & scientific | 2002 |
| Company Formation Solutions Limited | Extraterritorial | 2005 |
| Company Incorporations Worldwide Limited | Extraterritorial | 2015 |
| Company Multifloor Ltd | Construction | 2025 |
| Compass Cleaning Services (Doncaster) Limited | Administrative & support | 2022 |
| Compass Immigration Ltd | Professional & scientific | 2025 |
| Compass Site Engineering Services Limited | Extraterritorial | 2015 |
| Compass Vehicle Solutions Ltd | Wholesale & retail | 2011 |
| Competum Ltd | Other services | 2019 |
| Complete Coaching Solutions Limited | Arts & recreation | 2015 |
| Complete Electrical Testing Limited | Construction | 2021 |
| Complete Fire & Safety Limited | Public administration | 2015 |
| Complete Property Investment (Yorkshire) Ltd | Real estate | 2019 |
| Complete Roofing and Building Contractors Ltd | Construction | 2025 |
| Complete Utility Services Ltd | Energy | 2022 |
| Comply-Consultancy Ltd | Professional & scientific | 2008 |
| Composite Games Limited | Wholesale & retail | 2013 |
| Computastar Limited | Information & communication | 1996 |
| Computer ABC Systems Centre Ltd | Information & communication | 2025 |
| Computer Friendly Consultants Limited | Information & communication | 1999 |
| Comtekgb Ltd | Professional & scientific | 2024 |
| CON Spirito Group Ltd | Other services | 2010 |
| Concept Clinics (Rotherham) LLP | | 2007 |
| Concept Clinics Limited | Administrative & support | 2008 |
| Concept Draughting Services Ltd | Administrative & support | 2021 |
| Concept Fitness & Recovery Ltd | Arts & recreation | 2026 |
| Concept G E Ltd | Wholesale & retail | 2022 |
| Concept Joinery and Shopfitting Ltd | Administrative & support | 2017 |
| Concept Leasing Limited | Wholesale & retail | 2017 |
| Concept Manufacturing Ltd | Manufacturing | 2021 |
| CONCEPT2PROJECT Ltd | Professional & scientific | 2026 |
| Concilia Property Ltd | Real estate | 2019 |
| Concorde BGW Limited | Construction | 1990 |
| Concorde Interiors (London) Limited | Extraterritorial | 2005 |
| Concours Lifts Ltd | Manufacturing | 2016 |
| Concrete Mate Limited | Wholesale & retail | 2025 |
| Concrete Solutions Yorkshire Limited | Manufacturing | 2024 |
| Condacovo Ltd | Administrative & support | 2019 |
| Condat Limited | Wholesale & retail | 1985 |
| Conder Limited | Extraterritorial | 1999 |
| Conetrans Limited | Transport & logistics | 2023 |
| Coneygarth Farm Day Nursery Limited | Other services | 2006 |
| Confetti Candy Co Ltd | Wholesale & retail | 2025 |
| Confidence Trading Limited | Administrative & support | 1992 |
| Conform Safety Management Ltd | Construction | 2007 |
| Conisbrough Catering & Events Ltd | Hospitality | 2021 |
| Conisbrough Community Association Limited | Arts & recreation | 1997 |
| Conisbrough Community Library Limited | Arts & recreation | 2014 |
| Conisbrough Ivanhoe Primary Academy | Education | 2011 |
| Conisbrough Motor Spares & Repairs Limited | Wholesale & retail | 2024 |
| Conisbrough Ranger Ltd | Transport & logistics | 2021 |
| Coniston Services Doncaster Limited | Administrative & support | 2026 |
| Connect Freight & Logistics Ltd | Transport & logistics | 2024 |
| Connect Legal Limited | Administrative & support | 2019 |
| Connect Legal Translation Services Limited | Administrative & support | 2019 |
| Connected Rights Limited | Information & communication | 2024 |
| Connectus Business Solutions Ltd. | Information & communication | 2011 |
| Connor Bennett Editing Limited | Information & communication | 2024 |
| Connor Bryan TM Ltd | Public administration | 2022 |
| Connor Waine Ltd | Construction | 2025 |
| Connor's Property Rentals Limited | Real estate | 2023 |
| Connymc Ltd | Transport & logistics | 2020 |
| Conor Communications Ltd | Construction | 2025 |
| Conor Rogers Artist Ltd | Arts & recreation | 2021 |
| Conor's Camera Ltd | Information & communication | 2023 |
| Conquest Bidco Limited | Administrative & support | 2007 |
| Conroys Construction Ltd | Construction | 2018 |
| Cons Trans Limited | Transport & logistics | 2022 |
| Conscious Sole CIC | Health & social care | 2024 |
| Conser Consulting Limited | Professional & scientific | 2023 |
| Considered Hospitality Solutions Limited | Professional & scientific | 2025 |
| Consilium Risk Advisory Group Limited | Professional & scientific | 2026 |
| Consort Cash & Carry Limited | Professional & scientific | 1968 |