| Clumsy Bear Studio Limited | Information & communication | 2024 |
| Cluny Studio Limited | Professional & scientific | 2025 |
| CM2021 Ltd | Construction | 2021 |
| CMA Strategy Limited | Professional & scientific | 2016 |
| Cmac (Brighton) Limited | Hospitality | 2011 |
| Cmajor Software Ltd | Information & communication | 2023 |
| Cmbh Limited | Hospitality | 2014 |
| CML Reporting Limited | Other services | 2007 |
| CMR Advisory Ltd | Professional & scientific | 2018 |
| CMS Smart Ltd | Wholesale & retail | 2023 |
| Cntnr Limited | Hospitality | 2014 |
| Co-Smart Property Ltd | Real estate | 2016 |
| Coaching for Productivity and Growth Limited | Public administration | 2024 |
| Coachingpartner Limited | Information & communication | 2011 |
| Coachmans' Terrace RTE Company Limited | Households | 2005 |
| COACHWERKS2 Ltd | Real estate | 2020 |
| Coalface Events & Venues Limited | Other services | 2019 |
| Coalition Sports Limited | Education | 2024 |
| Coapt Limited | Real estate | 2004 |
| Coast and Country Electrical Limited | Construction | 2024 |
| Coast Corporate Finance Limited | Financial services | 2021 |
| Coast Production Limited | Administrative & support | 2005 |
| Coast to Capital Limited | Administrative & support | 2012 |
| Coast to Coast Direct Limited | Wholesale & retail | 2007 |
| Coast to Coast Investments Limited | Financial services | 2020 |
| Coastal City Ltd | Real estate | 2017 |
| Coastal Coverings Limited | Construction | 2001 |
| Coastal Heights Surveyors & Estates Ltd. | Professional & scientific | 2024 |
| Coastal House Investments Limited | Real estate | 2024 |
| Coastal Paving Ltd | Construction | 2007 |
| Coastal Postal Ltd | Transport & logistics | 2025 |
| Coastal Surveyors and Consultants Limited | Professional & scientific | 2023 |
| Coastline Automation Ltd | Information & communication | 2026 |
| Coastline Bathrooms and Refurbishments Ltd | Construction | 2019 |
| Coastline Contractors Ltd | Construction | 2025 |
| Coastline Removal Services Ltd | Transport & logistics | 2024 |
| Coated Limited | Professional & scientific | 2016 |
| Cobalt Hill Ltd | Other services | 2014 |
| Cobbled Close LLP | | 2013 |
| Cobblers Properties | Real estate | 1970 |
| Cobblers Records Ltd | Information & communication | 2019 |
| Cobden Arms Ltd | Hospitality | 2020 |
| Cobley Marketing Limited | Wholesale & retail | 2018 |
| Coburg Coffee Company Limited | Manufacturing | 1963 |
| Coburn & Baker Ltd | Manufacturing | 2012 |
| Cocco Gelato Limited | Hospitality | 2022 |
| Coco Creative Ltd | Administrative & support | 2020 |
| Coco's Bistro Ltd | Hospitality | 2024 |
| Coconut Milk Ltd | Wholesale & retail | 2026 |
| Cocopop Ltd | Hospitality | 2021 |
| Cocreate Hub Ltd | Professional & scientific | 2025 |
| Coda Digital Limited | Information & communication | 2013 |
| Coda Furniture Limited | Construction | 2022 |
| Codbass Ltd | Hospitality | 2025 |
| Code 200 Apps Limited | Information & communication | 2015 |
| Code POD Ltd | Information & communication | 2010 |
| Coded Futures Ltd | Wholesale & retail | 2016 |
| Codesortium Limited | Information & communication | 2008 |
| Coffee Tzar Kemptown Limited | Hospitality | 2019 |
| Coffee Tzar Limited | Hospitality | 2015 |
| Cognition Advisory Ltd | Administrative & support | 2025 |
| Cognitive Media Ltd | Professional & scientific | 2004 |
| Cognoscenti (Surrey) Limited | Information & communication | 1998 |
| Cogs Agency Limited | Administrative & support | 2004 |
| Cohen Davidson Limited | Professional & scientific | 1997 |
| Cohen Trading Ltd | Wholesale & retail | 2009 |
| Cohesion SBS Ltd | Transport & logistics | 2023 |
| Cohesive Minds Ltd | Professional & scientific | 2022 |
| Coin Connect Ltd | Professional & scientific | 2017 |
| Coinin Meala Limited | Professional & scientific | 2025 |
| Coins for Change Ltd | Health & social care | 2025 |
| Cokeham Manor Property Co. Limited | Real estate | 1958 |
| Colab Projects Ltd | Professional & scientific | 2026 |
| Colburt Marine Group Limited | Financial services | 2016 |
| Coldean Local Store Ltd | Wholesale & retail | 2015 |
| Coldean Neighbourhood Planning Forum Limited | Other services | 2022 |
| Coldean Pharmacy Limited | Wholesale & retail | 1988 |
| Coldharbour Connections Limited | Professional & scientific | 2021 |
| Coldrickconsulting Ltd | Professional & scientific | 2025 |
| Coldvan Ltd | Transport & logistics | 2016 |
| Coleman Hall Products Limited | Wholesale & retail | 2001 |
| Coleman Lewis Partnership Ltd | Construction | 2025 |
| Colemans Solicitors LLP | | 2006 |
| Colet Ltd | Real estate | 2019 |
| Colin Holden Associates Limited | Administrative & support | 1999 |
| Coliving Experience Ltd | Real estate | 2022 |
| Collaborative Design Studios Ltd | Professional & scientific | 2019 |
| Collaborative Law Ltd | Professional & scientific | 2023 |
| Collage Media Production Ltd | Manufacturing | 2022 |
| Collectarium Community Interest Company | Professional & scientific | 2024 |
| Collection Dance Limited | Arts & recreation | 2022 |
| Collectivai Limited | Information & communication | 2024 |
| Collective Action Brighton and Hove Ltd | Other services | 2024 |
| Collective Concepts Accounting Ltd | Professional & scientific | 2022 |
| Collective Concepts Group Ltd | Financial services | 2024 |
| College Kits Direct Limited | Wholesale & retail | 2009 |
| College of Classical Massage Limited | Health & social care | 2003 |
| Collette Harrison Consulting Limited | Administrative & support | 2020 |
| Collingridge Holdings Limited | Professional & scientific | 2020 |
| Collins Video Ltd | Information & communication | 2022 |