| Damian Davies Ltd | Other services | 2025 |
| Dangerfield Consultancy Ltd | Professional & scientific | 2022 |
| Daniel Jones Mortgages Ltd | Financial services | 2016 |
| Daniel Vaughan Consultancy Ltd | Professional & scientific | 2019 |
| DAP16 Limited | Health & social care | 2016 |
| Darkside Courier Services Ltd | Transport & logistics | 2025 |
| Databail Limited | Administrative & support | 1992 |
| Datum Recruiting Limited | Administrative & support | 2026 |
| David S Morgan Ltd | Professional & scientific | 2016 |
| Davies Coaches (Swansea) Ltd | Transport & logistics | 2011 |
| Davies Coaches Ltd | Transport & logistics | 2006 |
| Davies Translations Ltd | Other services | 2009 |
| Daybreak Pictures (Churchill) Limited | Information & communication | 2015 |
| Daybreak Pictures Limited | Information & communication | 2006 |
| Daybreak SPV Limited | Information & communication | 2015 |
| DB Fitness Ltd | Education | 2023 |
| DBS Property Management Limited | Households | 2021 |
| DC Garage Automotive Ltd | Wholesale & retail | 2025 |
| DCJ Composites Ltd | Manufacturing | 2013 |
| DE Lewis Engineering Ltd | Construction | 2016 |
| Dealer Forecourt Limited | Information & communication | 2026 |
| Deans Taxi and Minibus Hire Limited | Transport & logistics | 2025 |
| Dearl Health Tech Limited | Information & communication | 2025 |
| Decal Empire Ltd | Manufacturing | 2022 |
| Deheubarth Properties Ltd | Households | 2020 |
| Del-Excel Ltd | Education | 2014 |
| Delivercrew Ltd | Arts & recreation | 2023 |
| Deluxe Masterclasses Ltd | Education | 2024 |
| Deluxe Vapours Retail Ltd | Wholesale & retail | 2017 |
| Demetian Developments Ltd | Construction | 2000 |
| Deployed Consultancy Ltd | Information & communication | 2023 |
| Designyo Ltd | Manufacturing | 2023 |
| Detour Solutions Limited | Information & communication | 2017 |
| Devereaux Drive (Carmarthen) Ltd | Households | 2024 |
| DGD Safety Ltd | Professional & scientific | 2024 |
| DGW Electrical Contractors Limited | Construction | 2010 |
| DHE Payroll Services Ltd | Administrative & support | 2025 |
| Diagnostics Tumble Limited | Extraterritorial | 2025 |
| Diamond Golf Management Ltd | Professional & scientific | 2015 |
| Diamond Rope Access Limited | Construction | 2018 |
| DIG Africa Limited | Mining & quarrying | 2024 |
| DIG Civil Engineering Limited | Professional & scientific | 2019 |
| DIG International Group Limited | Mining & quarrying | 2019 |
| Dignify Community Interest Company | Health & social care | 2008 |
| Dignify Words Limited | Information & communication | 2025 |
| Dimax Aquatic Services Ltd | Other services | 2018 |
| Dimax Gymnastics Ltd | Other services | 2018 |
| Dimension Drawing Services Ltd | Professional & scientific | 2009 |
| Direct Engineering (S. W.) Ltd | Manufacturing | 2010 |
| Direct Meat Supplies Limited | Wholesale & retail | 1986 |
| Discount Perfumes and Aftershaves Ltd. | Wholesale & retail | 2008 |
| Discsimple Limited | Education | 2016 |
| Dive Team Limited | Real estate | 1998 |
| Dividers Group Holdings Limited | Manufacturing | 2018 |
| DJ Smoove Limited | Information & communication | 2016 |
| DJ Upvc UK Ltd | Construction | 2013 |
| DK Workwear Ltd | Professional & scientific | 2018 |
| Dklell Limited | Construction | 2018 |
| DLG Ltd | Professional & scientific | 2015 |
| DLP Properties Limited | Real estate | 2025 |
| Dluxebloom Ltd | Wholesale & retail | 2022 |
| DMC Interiors Ltd | Manufacturing | 2016 |
| DME Engineers Ltd | Construction | 1998 |
| Dmwsl 575 Limited | Professional & scientific | 2007 |
| Dmwsl 678 Limited | Information & communication | 2011 |
| DNH Barber Limited | Other services | 2017 |
| Doggy Desserts Collective Ltd | Wholesale & retail | 2026 |
| Donelan & Co Ltd | Real estate | 2022 |
| Dorian Heel Bar Limited | Other services | 2009 |
| Dormy Care Consultancy Ltd | Professional & scientific | 2026 |
| Douglas and Cleaver Ltd | Wholesale & retail | 2019 |
| Down to Earth (Wales) Ltd | Construction | 2014 |
| Downlighting Ltd | Information & communication | 2014 |
| DPA Law LLP | | 2009 |
| DR Edwards Ltd | Construction | 2018 |
| DR Ismail Limited | Wholesale & retail | 2025 |
| DR Maintenance Solutions Ltd | Professional & scientific | 2025 |
| Dr&J Property Ltd | Real estate | 2022 |
| Dragon Artworks Limited | Information & communication | 2024 |
| Dragon BIO Clean Ltd | Administrative & support | 2026 |
| Dragon Driveways Ltd | Construction | 2016 |
| Dragon Engineering Services Ltd | Manufacturing | 1997 |
| Dragon Estate Management Limited | Real estate | 2007 |
| Dragon Fine Foods Limited | Wholesale & retail | 1998 |
| Dragonarch Developments Limited | Construction | 2025 |
| Dragwn Ltd | Wholesale & retail | 2025 |
| Draig Ecology Ltd | Professional & scientific | 2022 |
| Draig Holdings CYF. | Financial services | 2025 |
| Draig MA Ltd | Arts & recreation | 2022 |
| Draig Renew EV CYF | Water & waste | 2025 |
| Dream Design Renovations Ltd | Real estate | 2023 |
| Dringo Limited | Construction | 2024 |
| Drive Wise and Well Limited | Education | 2019 |
| Driveline Vehicle Services Ltd | Wholesale & retail | 2025 |
| DRJ Car Sales Ltd | Wholesale & retail | 2021 |
| DRJ Property Holdings Ltd | Financial services | 2025 |
| DRL Partitions Limited | Manufacturing | 2017 |
| Drop the Box Ltd | Wholesale & retail | 2023 |
| Drumaway Limited | Professional & scientific | 2006 |
| DRW Holidays Ltd | Real estate | 2025 |