| THE Youth Work Leadership LAB Limited | Education | 2025 |
| Theta Solutions Ltd | Health & social care | 2022 |
| Think Creatively C.I.C. | Arts & recreation | 2023 |
| Thomas Evans Group Ltd | Administrative & support | 2016 |
| Thomasville Construction Limited | Construction | 2021 |
| Thornbury Collection Services Limited | Administrative & support | 2002 |
| Thorne Technical & Training Services Ltd. | Professional & scientific | 2018 |
| Thought Root Media Ltd | Information & communication | 2019 |
| Tinman Leasing Ltd | Administrative & support | 2023 |
| Tinylittleroar Ltd | Wholesale & retail | 2020 |
| Tipsy Mule Ltd | Wholesale & retail | 2023 |
| Titular Tubes Ltd | Wholesale & retail | 2025 |
| TJP Tours Limited | Arts & recreation | 2021 |
| TJW Rail Ltd | Construction | 2018 |
| TK Developments Limited | Construction | 1985 |
| Togs Enterprises Limited | Professional & scientific | 2025 |
| TOM Prichard (Holdings) Limited | Professional & scientific | 2015 |
| TOM Prichard Contracting Limited | Construction | 2005 |
| TOM Prichard Properties Limited | Real estate | 2015 |
| Tomport Properties Ltd | Real estate | 2019 |
| Total Electrical Solutions (RCT) Ltd | Construction | 2024 |
| Total Team Building Limited | Professional & scientific | 2005 |
| Tourniglo Limited | Professional & scientific | 2012 |
| Town Garage (Llantrisant) Limited | Wholesale & retail | 2024 |
| Town Garage (Rentals) Limited | Real estate | 2024 |
| Town Motor Factors Limited | Wholesale & retail | 2025 |
| Town Motor Vehicles Limited | Wholesale & retail | 2025 |
| TPS London Sofa Company Ltd | Manufacturing | 2022 |
| TR Eyes Limited | Wholesale & retail | 2018 |
| Trade Frames Direct (UK) Ltd | Wholesale & retail | 2007 |
| Tradeplas U.K Ltd | Wholesale & retail | 2022 |
| Training Matters Ltd | Professional & scientific | 2025 |
| Transflo Ltd | Transport & logistics | 2025 |
| Travel and Lifestyle Trends Ltd | Wholesale & retail | 2024 |
| Travel RK Ltd | Transport & logistics | 2019 |
| Treferig Ltd | Households | 2024 |
| Trigger Happy Creative Limited | Information & communication | 2023 |
| Trinity Foundation Ltd | Hospitality | 2026 |
| Trio Building Contractors Ltd | Construction | 2014 |
| Trio Group Holdings Ltd | Financial services | 2023 |
| Trio Mechanical Services Ltd | Construction | 2016 |
| Trio Solutions Ltd | Construction | 2019 |
| True Blue Scene Ltd | Professional & scientific | 2025 |
| Trustmark Design and Print Limited | Professional & scientific | 2007 |
| TTE Holdings Ltd | Financial services | 2023 |
| Tuitek Ltd | Manufacturing | 2022 |
| Tulip(Wales) Ltd | Hospitality | 2016 |
| Turnplug Limited | Real estate | 1989 |
| Two Foxes Limited | Construction | 2023 |
| Ty-Carreg Holdings Limited | Other services | 2009 |
| Ty-Rhosyn Homes Limited | Real estate | 2012 |
| TŶ Calon Hiraeth Limited | Real estate | 2024 |
| UEM (WLS) Ltd | Manufacturing | 2021 |
| ULTIM8 Detailing Co. Ltd | Wholesale & retail | 2024 |
| Unicorn Inn Cardiff Ltd | Hospitality | 2023 |
| Unwaith ETO Limited | Construction | 2026 |
| V Hardwick Limited | Professional & scientific | 2019 |
| V8 Hosting Limited | Information & communication | 2014 |
| Valco Limited | Construction | 2002 |
| Vale Glazing Limited | Construction | 2026 |
| Vale Independent Financial Advisers Limited | Financial services | 2008 |
| Vale Laser Aesthetics Ltd | Health & social care | 2019 |
| Vale Laser Ltd | Other services | 2014 |
| Vale Laser Skin Ltd | Other services | 2021 |
| Vale of Glamorgan Hotel Limited | Hospitality | 1999 |
| Vale Specialist Cars Ltd | Wholesale & retail | 2015 |
| Vantixai Ltd | Education | 2023 |
| Vapourz LAB LLP | | 2018 |
| Vefit Official Ltd. | Wholesale & retail | 2021 |
| Venford Holdings Limited | Construction | 2015 |
| Ventrbox Limited | Real estate | 2023 |
| VG Limited | Other services | 1960 |
| Vishal Sharma Limited | Transport & logistics | 2024 |
| Visionware Limited | Wholesale & retail | 2025 |
| Vivace Consultancy Ltd | Professional & scientific | 2025 |
| Volume Technologies Ltd | Manufacturing | 2020 |
| Voxvia Limited | Administrative & support | 2008 |
| VP (Talbot Green) Limited | Financial services | 2019 |
| VPS Automotive Limited | Wholesale & retail | 2023 |
| VUE Consulting Ltd | Information & communication | 2023 |
| Vulcan Boiler Services Ltd | Professional & scientific | 2017 |
| W&W Legacy Group Ltd | Professional & scientific | 2025 |
| W.F.T. PUB Company Limited | Hospitality | 2017 |
| W.R. Bishop (Hepworth Parc) Limited | Wholesale & retail | 2018 |
| Wack.Clothing Ltd | Wholesale & retail | 2021 |
| Wander Woman Wellbeing and Fitness Ltd | Arts & recreation | 2025 |
| Washerman Rentals Limited | Administrative & support | 2004 |
| Waste Transfer Systems Ltd | Water & waste | 2011 |
| Watches of Wales Limited | Wholesale & retail | 2013 |
| Watkins Trading Limited | Professional & scientific | 2018 |
| Wcrn CYF | Information & communication | 2024 |
| WD Holdings Ltd | Real estate | 2015 |
| Well-Being Connect CIC | Health & social care | 2025 |
| West Taff Finance Limited | Real estate | 1979 |
| Westgate Sports Agency Limited | Arts & recreation | 1991 |
| Wheatsheaf Hotel Llantrisant Limited | Hospitality | 2020 |
| Whiteboxes Ltd | Professional & scientific | 2009 |
| Whiteknight Records Ltd | Information & communication | 2011 |
| Widi Limited | Professional & scientific | 2013 |
| Wilkins Property Services Ltd | Real estate | 2026 |