| Davies Independent Trader’S Limited | Households | 2025 |
| Davies Investment & Consulting Limited | Financial services | 2024 |
| Davies Investments Limited | Other services | 2022 |
| Davies Jones Properties Ltd | Real estate | 2026 |
| Davies Maintenance Group Ltd | Administrative & support | 2022 |
| Davies Management Group Limited | Real estate | 2017 |
| Davies Mobile Metals Limited | Manufacturing | 2026 |
| Davies Praedium Ltd | Construction | 2003 |
| Davies Property (Swansea) Limited | Real estate | 2019 |
| Davies R2R Group Ltd | Real estate | 2019 |
| Davies Security Group Limited | Financial services | 2022 |
| Davies Security Limited | Construction | 2001 |
| Davies-Logan Loss Assessors Ltd | Financial services | 2025 |
| Davjon Property Co Limited | Real estate | 2021 |
| Davnos Transport Limited | Transport & logistics | 2023 |
| DAW Property Ltd | Real estate | 2025 |
| Dawson & Cole Ltd | Wholesale & retail | 2025 |
| Dawson Ventures Limited | Wholesale & retail | 2024 |
| Dawsons Training Ltd | Administrative & support | 2021 |
| DAX Real Estate Ltd | Real estate | 2021 |
| Day Developments Group Ltd | Construction | 2024 |
| Day Properties Ltd | Construction | 2020 |
| Day's Mobility Limited | Wholesale & retail | 1994 |
| Day's Motor Group Limited | Professional & scientific | 1996 |
| Day's Motor Park Limited | Professional & scientific | 1993 |
| Day's Property Developments Limited | Construction | 2021 |
| Daylight Community Global Ltd | Other services | 2026 |
| Days Hire Limited | Professional & scientific | 1996 |
| Days Only Ltd | Hospitality | 2019 |
| Dayspring Resourcing Ltd | Information & communication | 2024 |
| Daytont Limited | Real estate | 1984 |
| Day’S Property Holdings Limited | Financial services | 2017 |
| DAZ Line Ltd | Transport & logistics | 2022 |
| DB Commercial Advice Co Limited | Financial services | 2025 |
| DB M Works Limited | Wholesale & retail | 2026 |
| DB Management & Consultancy Co Limited | Professional & scientific | 2025 |
| DB Mortgage Advice Co Limited | Financial services | 2024 |
| DB Transport Services Ltd | Transport & logistics | 2024 |
| DB1 Heating & Stoves Ltd | Construction | 2023 |
| DBF Trailers Ltd | Manufacturing | 2016 |
| DC Electrical (Swansea) Ltd | Construction | 2014 |
| DC Structural Services Limited | Construction | 2018 |
| Dccscleaning Services Ltd | Administrative & support | 2024 |
| DCE T&C Ltd | Professional & scientific | 2026 |
| DCF Technology Ltd | Information & communication | 2023 |
| DCG Property Management Ltd | Real estate | 2020 |
| Dcmemarketing Ltd | Real estate | 2019 |
| DCS Accident Repair Ltd | Wholesale & retail | 2025 |
| Dcsd Ltd | Manufacturing | 2009 |
| DCW Consultancy Limited | Real estate | 2018 |
| DCW Land Holdings Ltd | Real estate | 2019 |
| DCW Project Services Ltd | Construction | 2018 |
| DD Inspection Maintenance Ltd | Mining & quarrying | 2023 |
| DDB Building Services Limited | Construction | 2018 |
| DDJ Construction Ltd | Construction | 2023 |
| DDL190 Limited | Hospitality | 2015 |
| Ddraig Llwyth Limited | Arts & recreation | 2021 |
| DDT Properties Limited | Real estate | 2015 |
| DE Agricultura Limited | Professional & scientific | 2011 |
| DE LA Beche Limited | Health & social care | 2018 |
| DE Oliveira Santos Limited | Health & social care | 2020 |
| DE Outsourcing Limited | Administrative & support | 2024 |
| Dealmaker.Money Limited | Professional & scientific | 2017 |
| Dealtorder Limited | Administrative & support | 1998 |
| Dean & Thomas Limited | Construction | 2003 |
| Dean Phillips Building and Plastering Ltd | Construction | 2024 |
| Dean Vaughan Limited | Financial services | 2023 |
| Deasy Occupational Health Ltd | Health & social care | 2018 |
| Death Monkey Records Ltd | Wholesale & retail | 2017 |
| Debbie's School of Motoring Ltd | Other services | 2008 |
| Debono Homes Ltd | Real estate | 2017 |
| Debt Dissolver Limited | Other services | 2026 |
| Debugs Software Ltd | Wholesale & retail | 2025 |
| DEC Property Management Ltd | Real estate | 2024 |
| Decale Construction Limited | Construction | 2001 |
| Deccan Flavours PVT Limited | Hospitality | 2026 |
| Deckbase Developments Limited | Real estate | 1988 |
| Decorsem Ltd | Information & communication | 2025 |
| Deep Blue Properties Limited | Real estate | 2022 |
| Deeys Beauty Limited | Other services | 2025 |
| Deezah Botanica Ltd | Manufacturing | 2024 |
| Deezback Resources Ltd | Wholesale & retail | 2024 |
| Defender Universe Ltd | Wholesale & retail | 2026 |
| Defensive Music Ltd | Information & communication | 2011 |
| Defensive Music Publishing Intl. Ltd | Information & communication | 2012 |
| Defiance Fitness Ltd | Education | 2020 |
| Defriend Limited | Professional & scientific | 2011 |
| Defy Time Cosmetics Limited | Health & social care | 2010 |
| Defy Time Limited | Health & social care | 2005 |
| Defy Time Swansea Limited | Other services | 2014 |
| Defyne by Sheridan Phillips Ltd | Other services | 2025 |
| Dehbokri Holdings Ltd | Real estate | 2006 |
| Deian Limited | Financial services | 2012 |
| Dela Vega's Health Care and Services Ltd | Health & social care | 2021 |
| Delano Homes Ltd | Real estate | 2019 |
| Delftcom Ltd | Wholesale & retail | 2013 |
| Deli Plus Limited | Hospitality | 2003 |
| Delicious Pixels Ltd | Information & communication | 2021 |
| Delight-Anjy Limited | Wholesale & retail | 2025 |
| Deliver & Scarper Ltd | Transport & logistics | 2021 |