| Door Decor & More Limited | Wholesale & retail | 2003 |
| Door Fabrications Limited | Manufacturing | 2006 |
| Door System Installations Ltd | Construction | 2009 |
| Doorcloud Limited | Information & communication | 2016 |
| Doorworx Joinery Ltd | Construction | 2019 |
| Doorworx Ltd | Construction | 2019 |
| Dorian Holdings Ltd | Financial services | 2018 |
| Dorta Care Limited | Health & social care | 2021 |
| Dosa Bar Ltd | Hospitality | 2025 |
| Dosilak Ltd | Hospitality | 2026 |
| Dosoco Limited | Professional & scientific | 2023 |
| Dotty's Field Limited | Real estate | 2024 |
| Double a Content Creations Ltd | Information & communication | 2025 |
| Double Blessings Ltd | Hospitality | 2022 |
| Double K Heating and Plumbing Limited | Construction | 2017 |
| Double Luck SA4 Limited | Hospitality | 2023 |
| Doug MAN Limited | Professional & scientific | 2016 |
| Dough & Go Limited | Hospitality | 2019 |
| Dough Republic 44 Ltd | Hospitality | 2025 |
| Douglas MAY Property Ltd | Real estate | 2024 |
| Doulla Constructions Ltd | Construction | 2020 |
| Dovedale Court Management Company Limited | Households | 1998 |
| Dower Power Limited | Arts & recreation | 2023 |
| Dower Roofing Limited | Construction | 2024 |
| Dower Tech Ltd | Information & communication | 2026 |
| Down by Here CYF. | Hospitality | 2026 |
| Down to Earth Construction | Construction | 2014 |
| Down to Earth Project | Education | 2005 |
| Downie Property Commercial Limited | Real estate | 2026 |
| Downie Property Ltd | Real estate | 2010 |
| DP Construction SW Ltd | Construction | 2020 |
| DP Quality Ltd | Professional & scientific | 2026 |
| DPE Management Consultancy Limited | Professional & scientific | 2020 |
| DPE Packing Supplies Limited | Transport & logistics | 2024 |
| DPE Removals and Storage Limited | Transport & logistics | 2024 |
| DPF Electrical Services Limited | Construction | 2026 |
| DPM Motors Ltd | Wholesale & retail | 2021 |
| Dprice Builders Ltd | Construction | 2019 |
| Dpttransprt Ltd | Transport & logistics | 2023 |
| Dpvs Property Ltd | Real estate | 2023 |
| DR Chris Goodwin Limited | Health & social care | 2014 |
| DR D P Hughes ML Ltd | Health & social care | 2018 |
| DR Euan Hails Consulting Services Limited | Health & social care | 2021 |
| DR Hand Car Wash Ltd | Administrative & support | 2025 |
| DR Hydraulic Services Ltd | Manufacturing | 2020 |
| DR Khalid Negm Ltd | Wholesale & retail | 2025 |
| DR P Costanzo Cardiology Limited | Health & social care | 2021 |
| DR Pneumatik Ltd | Arts & recreation | 2025 |
| DR Rees Ltd | Health & social care | 2022 |
| DR Welch's Properties Ltd | Real estate | 2025 |
| DR. D.P. Hughes Limited | Health & social care | 2002 |
| DR. DEX Ltd | Wholesale & retail | 2026 |
| DR. Linzi Thomas Medicolegal Services Limited | Health & social care | 2016 |
| DR. Organic Limited | Manufacturing | 2007 |
| Draenen WEN Properties Limited | Real estate | 2025 |
| Dragon Agri Ltd | Wholesale & retail | 2020 |
| Dragon and Shamrock Limited | Wholesale & retail | 2019 |
| Dragon Assessment Services Limited | Financial services | 2013 |
| Dragon Carpets and Flooring Limited | Wholesale & retail | 2014 |
| Dragon Energy Solutions Ltd | Professional & scientific | 2023 |
| Dragon Fire and Water Ltd | Information & communication | 2021 |
| Dragon Fire Design Solutions Ltd | Public administration | 2025 |
| Dragon GAS Limited | Extraterritorial | 1981 |
| Dragon Generics Limited | Health & social care | 2025 |
| Dragon Groundworks Ltd | Construction | 2022 |
| Dragon Home Response Ltd | Other services | 2025 |
| Dragon Home Support Ltd | Health & social care | 2025 |
| Dragon IT Support Limited | Information & communication | 2009 |
| Dragon Kinetic Ltd | Wholesale & retail | 2025 |
| Dragon Legal Wills Ltd | Professional & scientific | 2026 |
| Dragon Logistics 1 Ltd | Transport & logistics | 2026 |
| Dragon Palace (Swansea) Limited | Hospitality | 2017 |
| Dragon Pharmacies (Holdings) Ltd | Financial services | 2014 |
| Dragon Pharmacies Ltd | Extraterritorial | 2013 |
| Dragon Pump Services Limited | Construction | 1998 |
| Dragon Roofing Contractors Ltd | Construction | 2003 |
| Dragon Security One Ltd | Administrative & support | 2026 |
| Dragon Sports Limited | Extraterritorial | 1977 |
| Dragon Training & Recruitment Ltd | Administrative & support | 2018 |
| Dragondentl Limited | Health & social care | 2023 |
| Dragonfiar Limited | Other services | 2016 |
| Dragonfruit Catering Ltd | Hospitality | 2024 |
| Dragonsgate Ltd | Real estate | 2024 |
| Dragony Property Limited | Real estate | 2015 |
| Draig Cyber Ltd | Extraterritorial | 2025 |
| Draig Hearing Ltd | Health & social care | 2022 |
| Draig LDN Ltd | Arts & recreation | 2026 |
| DRAINS4YOU Ltd | Water & waste | 2019 |
| Drakelow Battery Ltd | Construction | 2022 |
| Drakonim Limited | Information & communication | 2012 |
| Dramatic Futures Ltd | Information & communication | 2019 |
| Draper Developments (Swansea) Limited | Real estate | 2024 |
| Draw Construction (Wales) Limited | Administrative & support | 2019 |
| DRB Limited | Wholesale & retail | 2015 |
| Dreadnought Properties Limited | Real estate | 2018 |
| Dream Homes (Wales) Limited | Construction | 2008 |
| Dreams Massage Therapy Ltd | Health & social care | 2022 |
| Drefach New Builds Ltd | Construction | 2024 |
| Drgg Ltd | Health & social care | 2024 |
| Drift 30 Limited | Manufacturing | 2025 |