| Communitas Clinics Ltd. | Health & social care | 2007 |
| Community Champs Network CIC | Education | 2024 |
| Companion Clearance Limited | Water & waste | 2023 |
| Computer Information Systems Limited | Information & communication | 1998 |
| Conceited Ltd | Wholesale & retail | 2024 |
| Confiance Hair Care Ltd | Other services | 2025 |
| Confident Care 24/7 Ashford Ltd | Professional & scientific | 2019 |
| Confident Care 24/7 Crawley Ltd | Professional & scientific | 2019 |
| Confident Care 24/7 Northampton Ltd | Professional & scientific | 2019 |
| Confident CARE24/7 Ipswich Ltd | Professional & scientific | 2019 |
| Confluencial Limited | Other services | 2021 |
| Congolese Widows and Orphans Union | Other services | 2020 |
| Conifers Limited | Real estate | 1997 |
| Conqueror Homes Ltd | Real estate | 2011 |
| Conquerwealth Limited | Health & social care | 2016 |
| Constructive Investments Ltd | Real estate | 2009 |
| Consultechit Limited | Information & communication | 2017 |
| Contas Consultancy Ltd | Professional & scientific | 2023 |
| Contemporary Chef Viny Limited | Hospitality | 2020 |
| Continental Supermarket Limited | Wholesale & retail | 2007 |
| Conxchange PVT Ltd | Information & communication | 2021 |
| Cookland Group Ltd | Real estate | 2017 |
| Cool Car Service Ltd | Wholesale & retail | 2022 |
| Cool Look Barbers Ltd | Other services | 2020 |
| Cord Allstar Ltd | Administrative & support | 2025 |
| Core Productions 1 Ltd | Professional & scientific | 2023 |
| Corners and Crevices Limited | Administrative & support | 2024 |
| Corth Group Ltd | Health & social care | 2017 |
| Corunna Spot Ltd | Hospitality | 2021 |
| Cosmin Fashion Limited | Wholesale & retail | 2023 |
| Cost Matters UK Limited | Professional & scientific | 2024 |
| Cozy Heaven Ltd | Professional & scientific | 2024 |
| CR7 Food Centre Ltd | Wholesale & retail | 2026 |
| Craig Dean Studio Ltd | Arts & recreation | 2014 |
| Crawley Mobile Tyre Team Limited | Manufacturing | 2025 |
| Cream Vibes Ltd | Wholesale & retail | 2021 |
| Createsuk Ltd | Professional & scientific | 2021 |
| Cricket Lovers Global Ltd | Arts & recreation | 2022 |
| Croos Retail Ltd | Wholesale & retail | 2025 |
| Crowe Investment Ltd | Real estate | 2025 |
| Crown Drycleaners (Croydon) Ltd | Other services | 2024 |
| Crown Property Partners Limited | Real estate | 2014 |
| Croydon Accounting Services Limited | Professional & scientific | 2007 |
| Croydon Automotive Limited | Manufacturing | 2009 |
| Croydon Builders Limited | Construction | 2017 |
| Croydon Cars Rental Ltd | Administrative & support | 2014 |
| Croydon Churches Floating Shelter Limited | Other services | 2011 |
| Croydon Food Station Limited | Hospitality | 2024 |
| Croydon Glass Works Limited | Construction | 2002 |
| Croydon Lettings Limited | Real estate | 2011 |
| Croydon Property Management Limited | Households | 2026 |
| Croydon Tamil Sangam | Professional & scientific | 2019 |
| Croydon Tool Hire Limited | Administrative & support | 1976 |
| Crulssshhh-Beauty Ventures Limited | Wholesale & retail | 2026 |
| Crypthon Technologies Ltd | Wholesale & retail | 2025 |
| CS London Property Company Limited | Real estate | 2021 |
| Curley Skip Hire Limited | Water & waste | 1994 |
| CUTTIN2U Limited | Other services | 2019 |
| Cutting Edge Security Ltd | Wholesale & retail | 2026 |
| D & C Property Services Ltd | Construction | 2022 |
| D & D Carribean Catering Ltd | Wholesale & retail | 2024 |
| D Brow Limited | Other services | 2025 |
| D I Bold Limited | Construction | 2018 |
| D J Maintenance Co & Sons Limited | Construction | 2004 |
| D M a Builders Ltd | Construction | 2023 |
| D Martins Group Ltd | Administrative & support | 2024 |
| D Three Systems Limited | Wholesale & retail | 2021 |
| D&R Accounting Limited | Other services | 2018 |
| D&S Heating Limited | Other services | 2021 |
| D-Artfactory Limited | Arts & recreation | 2014 |
| D-Zone Limited | Manufacturing | 2021 |
| D. Dallas Group of Companies Ltd | Real estate | 2021 |
| D.I.F Drylining Ltd | Construction | 2018 |
| D.R.H Solutions Ltd | Construction | 2025 |
| D976 Ltd | Wholesale & retail | 2020 |
| DA Pizza Box Ltd | Hospitality | 2024 |
| DA Support Services Ltd | Health & social care | 2025 |
| Daily Dazzling Dawn Ltd | Information & communication | 2024 |
| Dalal Limited | Professional & scientific | 2011 |
| DAN Soji Health Care Limited | Health & social care | 2015 |
| Daniel Ilie Transport Ltd | Transport & logistics | 2020 |
| Danify Ltd | Wholesale & retail | 2025 |
| Danvers & Sons Limited | Other services | 2023 |
| DAR Usool WA Furoo Ltd | Education | 2025 |
| Daranjo Rail Solutions Ltd | Professional & scientific | 2023 |
| Daraturkman Limited | Manufacturing | 2016 |
| Dark Diamond Solutions Ltd | Construction | 2017 |
| Dark Media Group Limited | Information & communication | 2022 |
| Dark Pictures Film 3 Limited | Information & communication | 2019 |
| Darkdiamond Creations Limited | Wholesale & retail | 2016 |
| Darkztyles Inc Limited | Wholesale & retail | 2020 |
| Data Analytics Team Ltd | Professional & scientific | 2026 |
| Dataforce Innovations Limited | Information & communication | 2025 |
| Datatech Insights Ltd | Information & communication | 2023 |
| Daugtez Ltd | Transport & logistics | 2021 |
| Davids Therapeutic Pathway Ltd. | Health & social care | 2022 |
| Davis&Sandiford Ltd | Hospitality | 2019 |
| Daymosssonofmars Ltd | Information & communication | 2025 |
| Daytona London Ltd | Manufacturing | 2026 |
| DAZ Global Limited | Professional & scientific | 2025 |