| Deeds NOT Words Limited | Wholesale & retail | 2021 |
| Deejas Supreme Services Ltd | Manufacturing | 2023 |
| Deen Services Ltd. | Professional & scientific | 2015 |
| Deer Park Developments Limited | Construction | 2006 |
| Deer Park Properties Limited | Extraterritorial | 2004 |
| Deer Plastering and Property Development Ltd | Construction | 2025 |
| Dees Scaffold Limited | Construction | 2022 |
| Defence System Dynamics Limited | Information & communication | 2023 |
| Deffroier Limited | Water & waste | 2021 |
| Defy Agency Limited | Professional & scientific | 2020 |
| Defying Gravity Academy CIC | Arts & recreation | 2019 |
| Deimo Autocentre Ltd | Wholesale & retail | 2025 |
| Delamode (SW) Limited | Transport & logistics | 2018 |
| Delbury Group Ltd | Real estate | 2022 |
| Delcare Newport Ltd | Health & social care | 2023 |
| Delina Properties Ltd | Real estate | 2025 |
| Deliserve Limited | Wholesale & retail | 1993 |
| Deliveryco Ltd | Transport & logistics | 2020 |
| Delphi Court Management Company Limited | Households | 1978 |
| Delphinus Swimming Limited | Education | 2021 |
| Delta Electrical Systems Limited | Manufacturing | 2014 |
| Delta Goods Ltd | Wholesale & retail | 2018 |
| Dempsey Developments LLP | | 2022 |
| Denham Lighting Limited | Other services | 2013 |
| Denios Limited | Wholesale & retail | 2000 |
| Deniz Cafe Cottage Ltd | Hospitality | 2024 |
| Denlew Assets Limited | Real estate | 2025 |
| Dentabee Ltd | Information & communication | 2025 |
| Derek Crawley Limited | Education | 2013 |
| Derek Kilbride Limited | Construction | 2017 |
| Derek Mills and SON Limited | Construction | 2014 |
| Derma Bare Ltd | Health & social care | 2024 |
| Derosoft Ltd | Information & communication | 2013 |
| Deroz Group Limited | Wholesale & retail | 2026 |
| Deroz Limited | Real estate | 2025 |
| Derwen Fields Limited | Construction | 2024 |
| Desi Kitchen (NPT) Ltd | Hospitality | 2018 |
| Design Kitchens Limited | Manufacturing | 2023 |
| Design Place 101 Ltd | Professional & scientific | 2019 |
| Design With Nature Ltd | Professional & scientific | 2012 |
| Designedbydale Ltd | Wholesale & retail | 2025 |
| Deskbridge Ltd | Information & communication | 2026 |
| Destiny Recovery Ltd | Transport & logistics | 2021 |
| Destiny Sessions UK Ltd | Information & communication | 2025 |
| Deswood Building Services Limited | Real estate | 2011 |
| Details Barber Ltd | Other services | 2025 |
| Detected Music Ltd | Information & communication | 2026 |
| Determinant Limited | Information & communication | 2007 |
| Developing Property Solutions Limited | Real estate | 2025 |
| Development Coaching Ltd | Health & social care | 2019 |
| Development Process Ltd | Information & communication | 2000 |
| Developments Plus Holdings Limited | Financial services | 2021 |
| Developments Plus Ltd | Manufacturing | 2013 |
| Deviell Rental Ltd | Wholesale & retail | 2018 |
| Dewise Limited | Public administration | 2022 |
| Dewsland Park Management Company Limited | Households | 1977 |
| Dezines Internet Solutions Limited | Information & communication | 2000 |
| DF10 Promotions Ltd | Arts & recreation | 2024 |
| Dfyard Ltd | Administrative & support | 2018 |
| DG Blades Limited | Professional & scientific | 2023 |
| DG Gurung Holdings Limited | Financial services | 2025 |
| DGB Electrical & Lighting Limited | Manufacturing | 2003 |
| DGMOTORS1 Ltd | Wholesale & retail | 2020 |
| DGS (IW) Ltd | Construction | 2025 |
| DH Flooring and Tiling Limited | Construction | 2020 |
| DHC Sports Ltd | Arts & recreation | 2025 |
| Dhhr Consulting Limited | Professional & scientific | 2022 |
| Dhiyakrish Ltd | Wholesale & retail | 2024 |
| DHS Rail Ltd | Professional & scientific | 2015 |
| DHZ Investments Ltd | Real estate | 2019 |
| Diablo Equestrian Limited | Wholesale & retail | 2020 |
| Diamond Finance Associates Limited | Financial services | 2010 |
| Diamond Finish Decorating Ltd | Construction | 2025 |
| Diamond Hearing Services Limited | Wholesale & retail | 2012 |
| Diamond Island Wills and Estate Planning Ltd | Financial services | 2023 |
| Diamond Securities Limited | Administrative & support | 2003 |
| Diamond Valeting and Carwash Services Ltd | Administrative & support | 2025 |
| Diamonds 2010 Limited | Wholesale & retail | 2010 |
| Diana KLI Ltd | Health & social care | 2019 |
| Didh Ltd | Professional & scientific | 2022 |
| DIG for Vintage Ltd | Wholesale & retail | 2013 |
| Digi Health Tech Ltd | Information & communication | 2023 |
| Digi Survey Ltd | Information & communication | 2025 |
| Digichemistry Limited | Information & communication | 2013 |
| Digit Info Systems Limited | Information & communication | 2021 |
| Digital Destination Ltd | Professional & scientific | 2009 |
| Digital Dispatch Ltd | Wholesale & retail | 2024 |
| Digital Evolution Consulting (DEC) Ltd | Professional & scientific | 2018 |
| Digital Gnome Ltd | Information & communication | 2022 |
| Digital Marketing Dynamics Ltd | Arts & recreation | 2023 |
| Digital Television Services Ltd | Information & communication | 2014 |
| Digital Trade Property Ltd | Real estate | 2024 |
| Digital Transformation Contracting Limited | Professional & scientific | 2024 |
| Digital Wales TEC Ltd | Other services | 2015 |
| Digitalrankerz Limited | Information & communication | 2025 |
| Dilip Gurung Properties Ltd | Real estate | 2022 |
| Dimi's Ecomm Ltd | Information & communication | 2026 |
| Dinas Building Company Limited | Construction | 1960 |
| Dinas Country Club Caravans Limited | Hospitality | 2007 |
| Dinham Lettings Limited | Administrative & support | 2017 |