| Cullengineers Limited | Professional & scientific | 2021 |
| Cultureworks Limited | Professional & scientific | 2024 |
| Culverdene Freehold Limited | Households | 2008 |
| Cumulus Stack Ltd | Information & communication | 2022 |
| Curious Enterprises Limited | Health & social care | 2014 |
| Curious Toucan Limited | Information & communication | 2020 |
| Curry Spoon Ltd | Hospitality | 2017 |
| Curtiss-Wright Wimborne Limited | Manufacturing | 2022 |
| Custom Booker Limited | Information & communication | 2022 |
| Custom World Dorset Limited | Manufacturing | 2010 |
| Custom World Properties Ltd | Real estate | 2022 |
| Cuthberga Limited | Real estate | 2024 |
| Cutler Bros. Ltd. | Agriculture & fishing | 2002 |
| Cutler's Autos Ltd | Wholesale & retail | 2024 |
| Cutlers Commercials Ltd | Wholesale & retail | 2025 |
| Cutting Hedge Consultancy Ltd | Information & communication | 2014 |
| Cutting IT Fine (Hair Design) Ltd | Other services | 2015 |
| Cvggamboa Properties Ltd | Real estate | 2022 |
| CWG Solutions Limited | Information & communication | 2024 |
| Cyber Prodigy Limited | Information & communication | 2024 |
| Cyber Veil Ltd | Information & communication | 2021 |
| Cyberdyne Tech Limited | Information & communication | 2024 |
| Cyberou Limited | Information & communication | 2026 |
| Cybersolace Limited | Information & communication | 2015 |
| Cycla Ltd | Education | 2026 |
| Cygnus Business Limited | Professional & scientific | 2016 |
| Cytel Limited | Information & communication | 1998 |
| D & T Consultants Limited | Information & communication | 2006 |
| D 2 Design Limited | Professional & scientific | 1996 |
| D a 2000 Ltd | Construction | 2018 |
| D and I Retail Ltd | Wholesale & retail | 2018 |
| D Francis Landscapes Ltd | Administrative & support | 2021 |
| D Gent Contract Services Ltd | Professional & scientific | 2023 |
| D J Dalgleish Limited | Real estate | 2014 |
| D J Developments & Sons Ltd | Real estate | 2025 |
| D J Plumb and Heat Ltd | Construction | 2019 |
| D J Roofing Ltd | Construction | 2014 |
| D M Heating Reading Ltd | Construction | 2013 |
| D Milton Carpentry Ltd | Manufacturing | 2021 |
| D&J Properties Wimborne Limited | Real estate | 2022 |
| D&S Electrical Contracting Ltd | Construction | 2025 |
| D'Arda Consulting Limited | Professional & scientific | 2014 |
| D. and I. Harvey (Builders) Ltd. | Construction | 1997 |
| D.J. Holdings (Poole) Limited | Financial services | 2022 |
| D=MC2 Limited | Professional & scientific | 2008 |
| DA Costa Advisory Limited | Professional & scientific | 2026 |
| DA GT Limited | Professional & scientific | 2010 |
| DA Resilience Limited | Professional & scientific | 2016 |
| Da-Tech Computing Limited | Information & communication | 2009 |
| DAB Dorset Ltd | Construction | 2005 |
| Dacology Ltd | Information & communication | 2018 |
| Dacombe & Renaut Limited | Wholesale & retail | 1984 |
| Daedus Limited | Professional & scientific | 2020 |
| Dainton IT Services Limited | Information & communication | 2018 |
| Daintree Life Limited | Wholesale & retail | 2021 |
| Dakscom CIC | Financial services | 2023 |
| Dala Properties Ltd | Real estate | 2020 |
| Damavand Pro Limited | Wholesale & retail | 2022 |
| Damian Gunner Limited | Information & communication | 2004 |
| Dampney Boat Services LLP | | 2026 |
| Damson Mechanical Limited | Construction | 2012 |
| DAN Wood Plumbing Ltd | Construction | 2017 |
| Dandy Supplies Ltd | Wholesale & retail | 2021 |
| Danehurst Estate Agents Ltd | Real estate | 2022 |
| Daniel Leeland Limited | Education | 2025 |
| Dansar Precision Engineering Ltd | Professional & scientific | 2021 |
| Danvers Stanley Electrical Ltd | Construction | 2022 |
| Dany Dreams Ltd | Transport & logistics | 2019 |
| Darcey Grace Limited | Real estate | 2021 |
| Darcy Ward Racing Limited | Arts & recreation | 2011 |
| Dardani & Large Limited | Agriculture & fishing | 1964 |
| Dark Knight Pest Control Ltd | Administrative & support | 2020 |
| Dark Mountain Software Limited | Information & communication | 2019 |
| Darkish Limited | Information & communication | 2024 |
| Darmax Research Limited | Professional & scientific | 2020 |
| Darren Harris Groundcare Ltd | Other services | 2011 |
| Darren Wrann Limited | Extraterritorial | 2022 |
| Dash Engineering Consultancy Ltd | Professional & scientific | 2023 |
| Dash Mgmt Ltd | Information & communication | 2023 |
| Data Based Learning Limited | Information & communication | 2021 |
| Data Change Management Ltd | Information & communication | 2023 |
| Data Heidi Consulting Limited | Professional & scientific | 2025 |
| Data Management Consultancy Services Ltd | Information & communication | 2012 |
| Data Management Specialists Ltd | Information & communication | 2017 |
| Databeast Ltd | Information & communication | 2013 |
| Datalogica Ltd | Information & communication | 2018 |
| Datamatic London Ltd | Information & communication | 2021 |
| Dataprime Limited | Information & communication | 2017 |
| Dataspec Consulting Limited | Information & communication | 2012 |
| Datlair Limited | Information & communication | 2025 |
| Datuza Technology Consulting Ltd | Information & communication | 2023 |
| Dave Mucker Cheeseman Limited | Construction | 2015 |
| David Bellini Display Solutions Ltd | Professional & scientific | 2016 |
| David Blunt Consulting Ltd | Professional & scientific | 2022 |
| David Downer Travel Ltd | Administrative & support | 2024 |
| David Everingham Conservation Limited | Arts & recreation | 2008 |
| David Glen Limited | Extraterritorial | 1993 |
| David Health Solutions Limited | Professional & scientific | 2013 |
| David Hollingworth Ltd | Professional & scientific | 2013 |
| David Joyner Couriers Limited | Transport & logistics | 2018 |