| Congham Hotels Limited | Hospitality | 2011 |
| Coniston Ullswater Limited | Real estate | 2009 |
| Conscious Construction Limited | Construction | 2020 |
| Construck (Norfolk) Ltd | Construction | 2025 |
| Construction & Electrical Safety Services Limited | Professional & scientific | 2000 |
| Consult Construct (Norfolk) Limited | Professional & scientific | 2026 |
| Consultancy Cambridge Group Limited | Professional & scientific | 2018 |
| Consultancy for a Change Ltd | Information & communication | 2025 |
| Content by Design Ltd | Information & communication | 2019 |
| Contours Beauty Limited | Other services | 2014 |
| Contract Builders Direct Ltd | Construction | 1998 |
| Contract Builders Management Company Limited | Real estate | 2012 |
| Controlwish Limited | Construction | 2018 |
| Coocumber (Norfolk) Limited | Wholesale & retail | 2026 |
| Cook Racing Limited | Administrative & support | 2020 |
| Cooks Furnishings, Carpets & Interiors Limited | Wholesale & retail | 2015 |
| Cookshop Hunstanton Ltd | Wholesale & retail | 2023 |
| Cool Climate Solutions Ltd | Construction | 2023 |
| Coopers Court (Kings Lynn) Management Company Limited | Households | 2007 |
| Copeman Construction Services Ltd | Construction | 2019 |
| Copeman Property Limited | Real estate | 2020 |
| Cork Brothers Limited | Real estate | 1955 |
| Cornerstone JET Limited | Wholesale & retail | 2014 |
| Cosmic Prints Ltd | Manufacturing | 2023 |
| Cotswold Creations Limited | Manufacturing | 2023 |
| Cottage Consultants Limited | Professional & scientific | 1992 |
| Cotton Mill Property Company (St.Albans)Limited | Real estate | 1966 |
| Coulten & Coulten Limited | Real estate | 1981 |
| Counting House Quay Limited | Hospitality | 2025 |
| Country Consulting Limited | Professional & scientific | 2021 |
| Country Contractors (Norfolk) Limited | Construction | 2021 |
| Country Holdings (Norfolk) Limited | Real estate | 2022 |
| Country Land Services Ltd | Administrative & support | 2017 |
| Country Lettings (Norfolk) Limited | Real estate | 2022 |
| Country Properties (Norfolk) Limited | Real estate | 2022 |
| Countrywise Outdoor Leisure Limited | Administrative & support | 2011 |
| Courtyard Barns Management Company Limited | Real estate | 2016 |
| Courtyard Investments (CM) Limited | Administrative & support | 2022 |
| Cozy Homes Grup Ltd | Real estate | 2024 |
| CR Lifting Services Ltd | Manufacturing | 2020 |
| Crannis Properties Limited | Real estate | 1988 |
| CRB Restaurants Limited | Hospitality | 2023 |
| Crea Norfolk CIC | Education | 2021 |
| Creake Business Park Limited | Real estate | 2015 |
| Creative Global Industries Limited | Wholesale & retail | 2002 |
| Creative Resin Design Limited | Construction | 2019 |
| Creativeportal Ltd | Information & communication | 2015 |
| Creature Care Ltd | Wholesale & retail | 2019 |
| Crisp Property Development Ltd | Construction | 2019 |
| Crisp Property Holdings Ltd | Real estate | 2023 |
| Criteria Cars (UK) Limited | Wholesale & retail | 2008 |
| Croptek AD Limited | Wholesale & retail | 2023 |
| Croptek BIO Ltd | Extraterritorial | 2009 |
| Croptek Ltd | Agriculture & fishing | 2007 |
| Croptek Organic Ltd | Other services | 2020 |
| Croptrak Ltd | Professional & scientific | 2022 |
| Crossman Connections Ltd. | Professional & scientific | 2018 |
| Crow Hall Barns Residents Limited | Households | 1995 |
| Crow Hall Downham Market Management Company Limited | Real estate | 2004 |
| Crowhurst Projects Limited | Professional & scientific | 2026 |
| Crown Civils Ltd | Construction | 2024 |
| Crown Oak Furniture Limited | Wholesale & retail | 2017 |
| Crown Property Solutions Limited | Construction | 2013 |
| Cruso & Wilkin Farms Ltd | Administrative & support | 2019 |
| CS Walkwood Ltd | Wholesale & retail | 2025 |
| Csachappell Ltd | Wholesale & retail | 2024 |
| Csense Solutions Ltd | Other services | 2017 |
| Csln Education Ltd | Extraterritorial | 2026 |
| CSM Rentals Limited | Transport & logistics | 2016 |
| CSO Construction Limited | Construction | 2014 |
| CSO Developments Limited | Construction | 2019 |
| Ctron Limited | Construction | 2024 |
| Cu.Tech.Zn.Ornamental Ltd | Construction | 2002 |
| Cuba Libre Restaurant & Bar Ltd | Hospitality | 2021 |
| Cull's of Norfolk Ltd | Wholesale & retail | 2018 |
| Culnells Barns Limited | Real estate | 2013 |
| Cuniculus Surveying Limited | Extraterritorial | 2009 |
| Curiosus Services Ltd | Professional & scientific | 2024 |
| Curtis & Malby Limited | Professional & scientific | 2025 |
| Curtis Home Improvements Limited | Construction | 2016 |
| Curzon (Norfolk) Limited | Manufacturing | 2015 |
| Cusack & Wells Property Holdings Ltd | Real estate | 2026 |
| Cutting Edge Content Limited | Public administration | 2006 |
| CV Fencing and Landscaping Ltd. | Administrative & support | 2012 |
| CV Insight Limited | Information & communication | 2006 |
| CVH Improvements Ltd. | Construction | 2016 |
| CW Group (Eastern) Limited | Professional & scientific | 2015 |
| CW Prints Ltd | Arts & recreation | 2024 |
| CWA Enterprises Limited | Education | 1993 |
| CWJ Leisure Limited | Hospitality | 2018 |
| CXK Electrical Limited | Construction | 2022 |
| D & B Plumbing & Mechanical Services Ltd | Construction | 2023 |
| D & C Cars Limited | Wholesale & retail | 2003 |
| D & C Developments Norfolk Ltd | Construction | 2021 |
| D & H Direct Limited | Wholesale & retail | 2015 |
| D & J Fenland Developments Limited | Construction | 2018 |
| D & O Motor Services Limited | Manufacturing | 2016 |
| D & R Building Limited | Real estate | 2008 |
| D & S Drainage Limited | Water & waste | 2013 |
| D B Building Conservation Limited | Construction | 2023 |