| T .S. Rees Holdings Limited | Mining & quarrying | 2018 |
| T C Agriculture Limited | Wholesale & retail | 2019 |
| T ED Langley Ltd | Wholesale & retail | 2003 |
| T G Couriers 25 Ltd | Wholesale & retail | 2025 |
| T J English Limited | Professional & scientific | 2013 |
| T M Sterling Ltd | Professional & scientific | 2018 |
| T&S Contracting Ltd | Construction | 2026 |
| T. Crandon Management Limited | Financial services | 2019 |
| T.D. Williams (Brynamman) Limited | Transport & logistics | 2004 |
| T.D.H. Welding Limited | Arts & recreation | 1992 |
| T.E.K Automotive Limited | Wholesale & retail | 2023 |
| T.S. Rees (Tonmawr Quarry) Limited | Mining & quarrying | 1989 |
| T.W Ventilation Services Ltd | Manufacturing | 2019 |
| T11 Media Ltd | Information & communication | 2004 |
| Table 51 Productions Ltd | Information & communication | 2025 |
| Taffia Limited | Wholesale & retail | 2022 |
| TAI Asbri Cyfyngedig | Administrative & support | 2007 |
| TAI Consultancy Limited | Administrative & support | 2021 |
| Taid Property Limited | Professional & scientific | 1982 |
| Tailored Consultancy Ltd | Professional & scientific | 2022 |
| Tailwind Cycles Ltd | Wholesale & retail | 2024 |
| Talbot Community Centre | Other services | 2003 |
| Talis Management Limited | Administrative & support | 2022 |
| Talk Together (Wales) Limited | Information & communication | 2007 |
| Tallify Bookkeeping Ltd | Professional & scientific | 2025 |
| Tamil Arts & Culture School (Tacs Wales) | Education | 2009 |
| Tamim Tandoori Limited | Hospitality | 2023 |
| Tanio Ltd. | Arts & recreation | 1985 |
| TAO Hair Culture Ltd | Other services | 2007 |
| Taps&Caps Ltd | Wholesale & retail | 2021 |
| Tardu Agency Ltd | Wholesale & retail | 2021 |
| Tardu Ltd | Wholesale & retail | 2019 |
| Target Change Solutions Limited | Information & communication | 2011 |
| Target Point Limited | Professional & scientific | 2006 |
| Tarian Commercial Finance Limited | Professional & scientific | 2025 |
| Taro Designs UK Limited | Wholesale & retail | 2022 |
| Tarw Leisure Bridgend Limited | Hospitality | 2025 |
| Tarw Security Ltd | Administrative & support | 2022 |
| Tarwci Lettings and Management Ltd | Real estate | 2025 |
| Tasha's Shop Limited | Wholesale & retail | 2023 |
| Tassbrook Properties Limited | Real estate | 2001 |
| Taste of Hungary Ltd | Hospitality | 2025 |
| Taste of Wales Hampers Limited | Hospitality | 2025 |
| Taurus (Sales) UK Ltd. | Manufacturing | 2000 |
| Taurus GB Limited | Extraterritorial | 2009 |
| Taurus Tape Ltd | Wholesale & retail | 2018 |
| Taybridge Soultions Ltd | Professional & scientific | 2025 |
| Taylors MOT Services Ltd | Wholesale & retail | 2019 |
| TBD (Owen Holland) Limited | Manufacturing | 2003 |
| TBD Owen Holland Holdings Limited | Manufacturing | 2014 |
| Tcrm Technology Limited | Information & communication | 2010 |
| TDA Clarke Enterprise Ltd | Hospitality | 2019 |
| TDW Distribution Limited | Transport & logistics | 1976 |
| Tea Cosy Retrofit Limited | Professional & scientific | 2026 |
| Techbray Limited | Extraterritorial | 2026 |
| Techcefacos Group CIC | Information & communication | 2025 |
| Techfray Limited | Information & communication | 2024 |
| Techgate Limited | Information & communication | 2024 |
| Techify Plus Ltd | Information & communication | 2009 |
| Technical Support and Cleaning Limited | Administrative & support | 2021 |
| Technicated Ltd | Information & communication | 2026 |
| Technivac Limited | Manufacturing | 1985 |
| Technoleg Limited | Professional & scientific | 1997 |
| Technovent Limited | Manufacturing | 1985 |
| Techwood Limited | Extraterritorial | 2025 |
| Tecm Management Ltd | Professional & scientific | 2020 |
| Tedd Construction Ltd | Construction | 2024 |
| Tegfan 360 Limited | Real estate | 2025 |
| Telbridge Ltd | Information & communication | 2003 |
| TEM Contracting Limited | Professional & scientific | 2016 |
| Tempest Enterprises Ltd | Wholesale & retail | 2005 |
| Terfyn Ltd | Financial services | 2024 |
| Termbray Limited | Information & communication | 2024 |
| Termlake Limited | Extraterritorial | 2024 |
| Termshare Limited | Professional & scientific | 1996 |
| Termview Limited | Extraterritorial | 2025 |
| Ternpark Limited | Extraterritorial | 2025 |
| Ternvale Limited | Extraterritorial | 2026 |
| Terry Reffell (Pencoed) Limited | Wholesale & retail | 1974 |
| Tersus Engineering Ltd | Wholesale & retail | 2026 |
| Tesla Travel Limited | Transport & logistics | 2020 |
| Tesog Limited | Wholesale & retail | 2018 |
| TFC Publishing Limited | Information & communication | 2002 |
| TH Developments Construction and Landscaping Limited | Construction | 2026 |
| Thames Marketing Consultants Ltd | Wholesale & retail | 2013 |
| Thashwen Properties Ltd | Real estate | 2021 |
| THE Aesthetic Events Collective Ltd | Administrative & support | 2026 |
| THE Autism Centre Limited | Health & social care | 2024 |
| THE Avenue (Pencoed) Management Company Limited | Real estate | 2013 |
| THE Bespoke Brick Company Limited | Wholesale & retail | 2013 |
| THE Bluebell Hotel (Neath) Limited | Extraterritorial | 2008 |
| THE Bradley Bros Ltd | Construction | 2025 |
| THE Brick Slip Business Limited | Wholesale & retail | 2015 |
| THE Bridgend Association of Bowls Tennis and Squash Clubs Community Interest Company | Arts & recreation | 1913 |
| THE Brit Ltd | Hospitality | 2025 |
| THE Caravan Warehouse Spares Limited | Wholesale & retail | 2015 |
| THE Cardiff Coffee Company Limited | Wholesale & retail | 1996 |
| THE Caring Laundry Co Ltd | Other services | 2008 |
| THE Children's Day Nursery Limited | Education | 2013 |
| THE Chipyard (Bridgend) Limited | Hospitality | 2018 |