| Competent Solutions Ltd | Professional & scientific | 2016 |
| Competex Pro Limited | Professional & scientific | 2013 |
| Competition Analysis Limited | Professional & scientific | 2005 |
| Complete Analytics Limited | Information & communication | 2015 |
| Complete Bathrooms Norwich Ltd | Wholesale & retail | 2018 |
| Complete Build Norfolk Limited | Construction | 2022 |
| Complete Car Centre Ltd | Wholesale & retail | 2020 |
| Complete Caring Limited | Health & social care | 1998 |
| Complete CM Ltd | Arts & recreation | 2026 |
| Complete Concierge Ltd | Administrative & support | 2024 |
| Complete Drainage Norfolk Ltd | Water & waste | 2026 |
| Complete Energy Ltd | Other services | 2017 |
| Complete Eyecare Solutions Limited | Health & social care | 2010 |
| Complete Financial Centre Ltd | Professional & scientific | 2006 |
| Complete Fitness Gyms Limited | Arts & recreation | 2016 |
| Complete Interior Design Ltd | Professional & scientific | 2012 |
| Complete Property Estates Ltd | Real estate | 2006 |
| Complete Tech Solutions Limited | Information & communication | 2021 |
| Completehouse (Lancaster) Limited | Construction | 2012 |
| Completely Business Ltd | Wholesale & retail | 2018 |
| Composite AK Ltd | Wholesale & retail | 2024 |
| Composite Decking Norwich Ltd | Administrative & support | 2025 |
| Composite Projects Limited | Manufacturing | 2015 |
| Compound Nutrition Limited | Hospitality | 2017 |
| Computer Nation Limited | Information & communication | 2013 |
| Computer Services (Norwich) Limited | Wholesale & retail | 2008 |
| Comtec Racing Limited | Other services | 1999 |
| Conaugh Properties Limited | Real estate | 2022 |
| Concentric Circles Theatre Company Ltd | Arts & recreation | 2012 |
| Concept 303 Limited | Professional & scientific | 2015 |
| Concept Bathrooms and Kitchens Limited | Wholesale & retail | 2006 |
| Concept Design Develop Limited | Construction | 2022 |
| Concorde Transport Services Limited | Transport & logistics | 2002 |
| Condimentum Limited | Manufacturing | 2017 |
| Condor Aviation Limited Liability Partnership | | 2002 |
| Conduity Capital PLC | Administrative & support | 2012 |
| Conesby Data Centre Limited | Information & communication | 2026 |
| Conesby Grid Limited | Energy | 2024 |
| Conesby Solar Farm Limited | Energy | 2018 |
| Confidea Ltd | Other services | 2024 |
| Conformity Solutions Limited | Professional & scientific | 2006 |
| Congruence Consultancy Limited | Professional & scientific | 2022 |
| Conisford Court Limited | Real estate | 2017 |
| Conker Bespoke Frames Limited | Manufacturing | 2022 |
| Conker Furniture Limited | Manufacturing | 2024 |
| Conlan School Limited | Education | 2008 |
| Connaught Kitchen Cafe Ltd | Hospitality | 2024 |
| Connect Structures Ltd | Professional & scientific | 2026 |
| Connect-Us Hub CIC | Education | 2026 |
| Connected Ecology Ltd | Professional & scientific | 2024 |
| Connected Legal Services Limited | Professional & scientific | 2016 |
| Connectex Ltd | Professional & scientific | 2019 |
| Connections Entertainment Limited | Arts & recreation | 2016 |
| Connectiva Ltd | Transport & logistics | 2026 |
| Connective Labs Limited | Information & communication | 2014 |
| Connoisseur Limited | Wholesale & retail | 1997 |
| Connor Sutton Transport Ltd | Transport & logistics | 2023 |
| Connors Mobile Tyres Ltd | Wholesale & retail | 2025 |
| Conpass Ltd | Construction | 2017 |
| Conprisa Limited | Public administration | 2015 |
| Conquer the Field Limited | Professional & scientific | 2016 |
| Conrad Building Services Limited | Construction | 2014 |
| Conrad Developments Ltd | Construction | 2024 |
| Conrad Global Group Limited | Professional & scientific | 2010 |
| Conrad Investment Holdings Ltd | Financial services | 2024 |
| Conrad Property (Thorpe Lodge) Limited | Construction | 2025 |
| Conrad Property Limited | Construction | 2016 |
| Conscious Cleaning Group Limited | Administrative & support | 2021 |
| Consensus Media Holdings Limited | Financial services | 2024 |
| Consensus Property Management Limited | Administrative & support | 2024 |
| Conservatives in Energy Limited | Other services | 2024 |
| Consignment GB Limited | Transport & logistics | 2013 |
| Consilium Financial Limited | Professional & scientific | 2014 |
| Consono Health Ltd | Professional & scientific | 2025 |
| Consort Road (AC) Limited | Real estate | 2024 |
| Constable Court Management Company Limited | Households | 2007 |
| Constance Louisa Limited | Real estate | 2020 |
| Constantia Brothers Music Limited | Arts & recreation | 1987 |
| Constitution Hill Developments Ltd | Construction | 2019 |
| Constitution Motors (Contracts) Limited | Other services | 1962 |
| Constitution Motors Limited | Real estate | 1959 |
| Construction & Commercial Services Limited | Construction | 1997 |
| Construction Assessment Services Limited | Professional & scientific | 2015 |
| Construction Cubed Limited | Construction | 2022 |
| Construction Skills Training Services Ltd | Administrative & support | 2015 |
| Constructive Mediation Ltd | Professional & scientific | 2025 |
| Consult Design Contract Limited | Construction | 2013 |
| Consult NOW Limited | Information & communication | 2016 |
| Consultancy Deployment Management Ltd | Professional & scientific | 2020 |
| Consultants Black Book Limited | Professional & scientific | 2008 |
| Consultants EN Planification Services Ltd | Construction | 2024 |
| Consulting Simplicity Limited | Information & communication | 2011 |
| Consultio/Consultius Limited | Professional & scientific | 2026 |
| Consultkgm Ltd | Information & communication | 2019 |
| Consultx Ltd | Manufacturing | 2024 |
| Consultxbh Ltd | Professional & scientific | 2019 |
| Consumer Search Partners Limited | Administrative & support | 2018 |
| Contact Electrical (Norwich) Ltd | Construction | 2001 |
| Contact Electrical and Mechanical Services Ltd | Extraterritorial | 2013 |
| Contact Electrical Holdings Ltd | Financial services | 2023 |