| Dark Moon Yards Limited | Professional & scientific | 2025 |
| David Gilbert Jewellery Limited | Wholesale & retail | 2025 |
| Davies & Lewis | | 1999 |
| Davies Breeding Kennels Limited | Agriculture & fishing | 2023 |
| Davies Lewis Baker Limited | Professional & scientific | 2018 |
| DC Sprinkler Systems Limited | Construction | 2024 |
| DE James Agricultural Engineers Limited | Manufacturing | 2016 |
| Dean Colman Plumbing & Heating Ltd | Construction | 2025 |
| Debinge Ltd | Health & social care | 2023 |
| Dejunk Ltd | Hospitality | 2023 |
| Delta Shield Ltd | Information & communication | 2025 |
| Deri Jones & Associates Limited | Professional & scientific | 2003 |
| Derwenlas Halls Limited | Real estate | 2023 |
| Detoju Concept Limited | Other services | 2022 |
| Devil's Bridge Falls Limited | Other services | 1982 |
| Devimead BSA Limited | Extraterritorial | 1995 |
| Devimead Limited | Extraterritorial | 2012 |
| Dgfp Ltd | Financial services | 2018 |
| DHD Mentrau Limited | Administrative & support | 2025 |
| Digihubwales Limited | Administrative & support | 2020 |
| Dinas Home Improvements Limited | Construction | 2023 |
| Diogel Events Limited | Administrative & support | 2018 |
| DJE Properties Limited | Real estate | 2015 |
| DLB Probate Services Limited | Professional & scientific | 2026 |
| Dorsim Ltd | Other services | 2020 |
| Downes Veterinary Limited | Professional & scientific | 2015 |
| Downhill Demons Ltd | Wholesale & retail | 2025 |
| Dragon Homes Ltd | Construction | 2021 |
| Dragon Laundry Ltd | Manufacturing | 2022 |
| Dragon Lettings Ltd | Real estate | 2023 |
| Dragon Logs Ltd | Agriculture & fishing | 2024 |
| Dragon Technologies Ltd | Professional & scientific | 2026 |
| Dragon Windows Ltd | Wholesale & retail | 2023 |
| Dragonfly Bistro Limited | Hospitality | 2018 |
| Dragonfly Solutions Limited | Information & communication | 2003 |
| Dragon’S Treasures Ltd | Wholesale & retail | 2025 |
| Driftwood Designs Limited | Manufacturing | 2015 |
| Drkenawi Ltd | Health & social care | 2025 |
| DSH (Aberystwyth) Limited | Water & waste | 2025 |
| Dulais Group CYF | Professional & scientific | 2017 |
| DUO Skip Hire (Aberystwyth) Limited | Water & waste | 2025 |
| DUO Skip Hire Limited | Water & waste | 2004 |
| Dyfed Powys Firearms Ltd | Wholesale & retail | 2018 |
| Dyfi Design Ltd | Professional & scientific | 2024 |
| Dyfi Events Limited | Arts & recreation | 2015 |
| Dylan Jones Consultants Limited | Wholesale & retail | 2020 |
| Dylan Jones Retail Consultants Limited | Wholesale & retail | 2021 |
| Dylan Jones Retail LLP | | 2011 |
| Dyma FI Cyfyngedig | Wholesale & retail | 2014 |
| Dyma NI Limited | Health & social care | 2020 |
| Dynamics TV CYF | Information & communication | 2025 |
| E H Williams Agri Services Limited | Agriculture & fishing | 2015 |
| E. LL. Hughes and Sons Limited | Construction | 2004 |
| Eastern Gate Property Ltd | Real estate | 2025 |
| Eastgate Dental Surgery Ltd | Health & social care | 2011 |
| Eco Hub Aber Ltd | Education | 2022 |
| Eidcymru | Public administration | 2014 |
| Eisa Tea Co. Ltd | Manufacturing | 2021 |
| Electra Business Services Limited | Professional & scientific | 2014 |
| Electrical Estimates Ltd | Construction | 2019 |
| Elementech Ltd | Information & communication | 2025 |
| Elhna Properties Limited | Real estate | 2023 |
| Ellaban Ltd | Health & social care | 2026 |
| Ellaway Environmental Ltd | Water & waste | 2013 |
| Ellis Coastal Developments Ltd | Construction | 2016 |
| Ellis D+B Ltd | Construction | 2016 |
| Ellis Development Company (Wales) Ltd | Construction | 2015 |
| Ellis Developments (Wales) Limited | Construction | 1999 |
| Ellis Properties (Wales) Ltd | Real estate | 2014 |
| Elon Properties Ltd | Real estate | 2019 |
| EMJ Electrical Ltd | Construction | 2013 |
| Emwela Transport Limited | Transport & logistics | 2000 |
| Energene Seeds Limited | Professional & scientific | 2020 |
| Enginova Health Systems Ltd | Administrative & support | 2025 |
| Enid Communications Ltd | Professional & scientific | 2023 |
| Ennyn C.I.C. | Education | 2019 |
| Eorhh Limited | Financial services | 2015 |
| EPC Cymru (Aber) CYF | Professional & scientific | 2021 |
| Epic Militaria Ltd | Wholesale & retail | 2006 |
| Equimaise Ltd | Other services | 2023 |
| Equinerd Ltd | Agriculture & fishing | 2020 |
| Equitation Partnership Limited | Education | 2014 |
| Eryl Fryn Ltd | Households | 2020 |
| Eryl Properties Limited | Real estate | 2026 |
| Esgee Consulting Ltd | Administrative & support | 2024 |
| Essnce Haus Ltd. | Professional & scientific | 2018 |
| ETD Developments Limited | Hospitality | 2021 |
| Evans Heating Ltd | Construction | 2022 |
| Evans Penlan CYF | Agriculture & fishing | 2014 |
| Evans Properties Aberystwyth Ltd | Real estate | 2017 |
| Ewenique Limited | Manufacturing | 2024 |
| Exchange Service Station Ltd | Wholesale & retail | 2023 |
| F a Rennie Ltd | Hospitality | 2026 |
| F Roberts Ltd | Households | 2021 |
| F&R Flooring Ltd | Wholesale & retail | 2017 |
| Falconers Group Ltd | Information & communication | 2021 |
| Fars Holdings Limited | Hospitality | 2025 |
| Fascionyx Medical Aesthetics Ltd | Health & social care | 2026 |
| Fatty G Ltd | Real estate | 2024 |
| Fays Restaurant & Lounge Ltd | Hospitality | 2022 |