| Dechrau Disglair Limited | Health & social care | 2010 |
| Definitive Consulting (Wales) Limited | Professional & scientific | 2009 |
| Deighton Property Ltd | Real estate | 2023 |
| Deliverays Limited | Other services | 2024 |
| Delme L. James Ltd | Construction | 2008 |
| Derwen Financial Planning Limited | Financial services | 2017 |
| Derwydd Services Ltd | Wholesale & retail | 2020 |
| Devran Pentre Ltd | Hospitality | 2025 |
| Dexters Hospitality Limited | Hospitality | 2015 |
| DG Quality Feeds Ltd | Manufacturing | 2012 |
| Dheeraj Consultancy Limited | Real estate | 2012 |
| DHW Davies Holdings Ltd | Real estate | 2024 |
| DHW Davies Limited | Real estate | 2016 |
| Diamond and Roberts Limited | Hospitality | 2022 |
| Diet Rebellion Sweet Company Ltd | Hospitality | 2021 |
| Digitalist P.C. | | 2017 |
| Dinefwr Homes Ltd | Construction | 2012 |
| Diocom Trade L.P. | | 2018 |
| Divergent Ideas Limited | Administrative & support | 2025 |
| DJ & SON Utilities Limited | Construction | 2024 |
| DJC Morgan Limited | Professional & scientific | 2011 |
| Djdistributions Limited | Wholesale & retail | 2025 |
| DJT Waste Removal Ltd | Water & waste | 2022 |
| Dkrt Properties Limited | Real estate | 2025 |
| DLJ Extractions Limited | Construction | 2020 |
| Do's R US Limited | Arts & recreation | 2011 |
| Dog Behaviour UK Ltd | Other services | 2023 |
| Dogs 4 Wildlife Ltd | Other services | 2019 |
| Dolgarreg Farm Ltd | Agriculture & fishing | 2025 |
| Dolren Cyfyngedig | Professional & scientific | 2025 |
| Donebyexperts Ltd | Information & communication | 2026 |
| Donnelly Fencing Ltd | Construction | 2020 |
| Dorian Bowen Construction Ltd | Construction | 2023 |
| Dorian Morgan Limited | Wholesale & retail | 2020 |
| Dotrproperties Limited | Real estate | 2021 |
| Doughmestic Ltd | Hospitality | 2025 |
| Down 2 Earth Property Solutions Limited | Construction | 2012 |
| DR Gupta Consultancy Limited | Real estate | 2010 |
| DR Hanna Jones Ltd | Health & social care | 2018 |
| DR Neil Jones Ltd | Real estate | 2023 |
| DR SBM Limited | Health & social care | 2019 |
| Dragon & Thistle Limited | Health & social care | 2018 |
| Dragon CAN FLY Limited | Extraterritorial | 2016 |
| Dragon Mobile Catering Limited | Wholesale & retail | 2011 |
| Dragon Press Bindery Limited | Manufacturing | 2017 |
| Dragon Stone Farm Ltd | Agriculture & fishing | 2026 |
| Dragon Wellness Limited | Health & social care | 2026 |
| Dragonpatch Capital Limited | Extraterritorial | 2014 |
| DRB Davies & Co Limited | Agriculture & fishing | 2013 |
| DRE TWT Limited | Arts & recreation | 2019 |
| Driftwood Pendine Limited | Hospitality | 2019 |
| Drindod Properties Ltd | Construction | 2015 |
| Driver Education Group Ltd | Education | 2023 |
| Driving School Network Ltd | Education | 2023 |
| Dryslwyn Community Shop Limited | Wholesale & retail | 2008 |
| Drywi CYF | Real estate | 2023 |
| DSS Rentals Limited | Real estate | 2024 |
| DTG Properties Limited | Real estate | 2016 |
| Dtph ARB & Groundworks Ltd | Agriculture & fishing | 2023 |
| Dunn's Property Ltd | Construction | 2023 |
| Dunns Engineering Resource Limited | Manufacturing | 1994 |
| Dutch Crunch Ltd | Extraterritorial | 2016 |
| DWC Safety Services Limited | Administrative & support | 2013 |
| DWP Associates Limited | Professional & scientific | 2018 |
| Dyce Investment Limited | Administrative & support | 2011 |
| Dyfed Alarms Limited | Construction | 1999 |
| Dyfed Insure Services Ltd | Financial services | 2025 |
| Dyfed Plant Services Ltd. | Manufacturing | 2022 |
| Dyfed Security Limited | Financial services | 2021 |
| Dyfed Tyres Limited | Wholesale & retail | 2017 |
| Dylark Ltd | Wholesale & retail | 2014 |
| Dynatech Group Ltd | Information & communication | 2024 |
| E Siggery Ltd | Administrative & support | 2021 |
| E. J. Thomas & SON Limited | Agriculture & fishing | 2014 |
| E.Daniels Ltd | Health & social care | 2025 |
| Eagle Accountancy (UK) Limited | Professional & scientific | 2011 |
| East Pool Farm Limited | Agriculture & fishing | 2009 |
| Eclectica Drindod Limited | Arts & recreation | 2005 |
| Eco Clean Group Ltd | Construction | 2019 |
| Eco Scapewales Ltd | Administrative & support | 2025 |
| Ecoenergy Training Limited | Construction | 2015 |
| Ecology Planning Ltd | Professional & scientific | 2009 |
| Ed's Bar Limited | Hospitality | 2010 |
| Ed's Restaurant Ltd | Hospitality | 2010 |
| Edernity Ltd | Wholesale & retail | 2023 |
| EDUC8 Beauty Ltd | Other services | 2026 |
| Edwards Mcnally Investments Ltd | Financial services | 2023 |
| Edwicker Consultancy Services Ltd | Professional & scientific | 2026 |
| Efail Ltd | Arts & recreation | 2020 |
| Eggerton Building Contractors Ltd | Construction | 2018 |
| Egni Solar Cymru Ltd | Construction | 2022 |
| Eiddo James CYF Limited | Construction | 2024 |
| Eiddo R James CYF | Real estate | 2025 |
| EKW Consult Ltd | Administrative & support | 2022 |
| Elaichi Indian Ltd | Hospitality | 2019 |
| Elbj Electrical Limited | Construction | 2008 |
| Electric MX Ltd | Wholesale & retail | 2016 |
| ELEV8 Homes Limited | Real estate | 2019 |
| ELEV8 Land & Property Limited | Real estate | 2015 |
| Elevate B C Ltd | Professional & scientific | 2017 |