| DRW Saer Coed CYF Limited | Manufacturing | 2021 |
| Dryhome Condensation Limited | Wholesale & retail | 2002 |
| Dryhome Ltd | Extraterritorial | 2010 |
| DS Air Conditioning Services Ltd | Construction | 2022 |
| DSG Speacilist Care Transport Limited | Transport & logistics | 2024 |
| DSK Lifemed Limited | Health & social care | 2024 |
| Dstf Ltd | Agriculture & fishing | 2020 |
| DTL Seren Spa Limited | Other services | 2017 |
| Dubco Limited | Wholesale & retail | 2026 |
| Duport Steel Works Limited | | 1911 |
| Dups Services Ltd | Professional & scientific | 2021 |
| DVF Motors Ltd | Agriculture & fishing | 2023 |
| DWD Waste Services Ltd | Water & waste | 2024 |
| Dyfed Auto Electrics Limited | Wholesale & retail | 2008 |
| Dyfed Developments Limited | Real estate | 2014 |
| Dyfed Menswear Limited | Wholesale & retail | 2003 |
| Dyfed Steels (Southern) Ltd | Wholesale & retail | 1998 |
| Dyfed Steels Limited | Wholesale & retail | 1976 |
| Dyfed Steels Mid-Wales Limited | Wholesale & retail | 2001 |
| Dynamic Shows and Events Ltd | Hospitality | 2025 |
| E & R Construction Services Limited | Professional & scientific | 2018 |
| E & S Jenkins Ltd | Hospitality | 2025 |
| E S P Environmental Limited | Professional & scientific | 1998 |
| Eaga EPC Ltd | Other services | 2020 |
| Eaga Group Limited | Administrative & support | 2014 |
| Eaga Ltd | Professional & scientific | 2019 |
| Eagle EYE Cleaning Services Ltd | Administrative & support | 2025 |
| Earles Logistics Ltd | Transport & logistics | 2026 |
| Eastgate Travel Limited | Administrative & support | 2013 |
| Easybooks Wales Ltd | Professional & scientific | 2009 |
| EBS Global Limited | Manufacturing | 2020 |
| Ecjbikes Ltd | Wholesale & retail | 2026 |
| Eco Installs Ltd | Construction | 2023 |
| Eco Plastering Systems Ltd | Construction | 2025 |
| Eco Reports Ltd | Professional & scientific | 2020 |
| Eco-Cymru Ltd | Professional & scientific | 2024 |
| Ecoheat Plumbing and GAS Services Ltd | Construction | 2022 |
| Ecopro Homes Limited | Construction | 2021 |
| Ecosure Retrofit Services Ltd | Administrative & support | 2025 |
| Ecotherm Installations Ltd | Construction | 2025 |
| Ecoxero Build Limited | Manufacturing | 2016 |
| EDC Cleaning Services Ltd | Administrative & support | 2017 |
| Eddie's Cabs Ltd | Transport & logistics | 2016 |
| Eden Lets Limited | Real estate | 2022 |
| Edeneil Kitchen Ltd | Hospitality | 2025 |
| Edwards&Harries Ltd | Other services | 2025 |
| Efficient Body Limited | Arts & recreation | 2005 |
| Egisss Ltd | Transport & logistics | 2023 |
| Egni Energy Limited | Professional & scientific | 2024 |
| Ehpd Ltd | Households | 2021 |
| Eiddo Samrah LLP | | 2023 |
| Eirianwen Idwallon Ltd | Manufacturing | 2020 |
| Eirllin Limited | Wholesale & retail | 2012 |
| Eirwyn James Plant Services Ltd | Agriculture & fishing | 2016 |
| EJS Electrical & Renewables Ltd | Construction | 2025 |
| EJS2026 Limited | Hospitality | 2026 |
| EL Pasco's World Fusion Food Ltd | Hospitality | 2025 |
| Elck Properties Limited | Real estate | 2024 |
| Elddir Ltd | Professional & scientific | 2021 |
| Eleanorhopeconsulting Ltd | Administrative & support | 2011 |
| Electra City Limited | Professional & scientific | 1990 |
| Elevate Solutions Consultancy Limited | Education | 2024 |
| Elexor Engineering Ltd | Construction | 2022 |
| Elgin Architecture and Design Ltd | Professional & scientific | 2015 |
| Elifim Ltd | Hospitality | 2023 |
| Elijah Consult Limited | Construction | 2021 |
| Elijah Homes Limited | Construction | 2018 |
| Elim Pentecostal Church Pontyates | Other services | 2007 |
| Elim Services Limited | Administrative & support | 2021 |
| Elis Barbers Ltd | Other services | 2025 |
| Eliza Empires Limited | Real estate | 2022 |
| Elizabeth Evans Beauty and Aesthetics Ltd | Other services | 2024 |
| Elizabeth Styles Commercial Interiors Consultancy Ltd | Professional & scientific | 2020 |
| ELK Machinery & Plant Hire Ltd | Administrative & support | 2019 |
| Ella's Event Catering Limited | Hospitality | 2024 |
| Ellanco Ltd | Administrative & support | 2025 |
| Elmera Holdings Limited | Administrative & support | 2024 |
| Elux Project Limited | Education | 2025 |
| Elven Enterprises Limited | Real estate | 2022 |
| Elysium Development and Testing Limited | Information & communication | 2017 |
| Elysium Investment Group Limited | Financial services | 2018 |
| Elysium Property Management Limited | Financial services | 2018 |
| Elysium Technology Group Limited | Information & communication | 2025 |
| Emandar Limited | Real estate | 2006 |
| Emanuel Heating & Plumbing Services Ltd | Construction | 2017 |
| Embedology Ltd | Information & communication | 2002 |
| Ember House Hospitality Ltd | Hospitality | 2026 |
| Emerge Advertising Limited | Professional & scientific | 2016 |
| Emilia MAY Gifts Limited | Wholesale & retail | 2014 |
| Emily Morris Wealth Management Ltd | Financial services | 2020 |
| Emlyn Lloyd Property Limited | Real estate | 2026 |
| Emma Ruth Developments Limited | Real estate | 2013 |
| Empire Carpentry Interiors Ltd | Construction | 2016 |
| Emyr Huws Properties Ltd | Real estate | 2026 |
| Enchanted Market Ltd | Wholesale & retail | 2024 |
| Encouraging Excellence Consultancy Ltd | Professional & scientific | 2018 |
| Endaf Owens Fabrication Ltd | Manufacturing | 2019 |
| Endgame Films Limited | Information & communication | 2008 |
| Enesem Limited | Information & communication | 2016 |
| Enfys Mediation Services Ltd | Professional & scientific | 2025 |