| Thyme Construction Ltd | Construction | 2022 |
| Tiaret Ltd | Administrative & support | 2022 |
| Tickety-Boo Cleaning Limited | Administrative & support | 2013 |
| Tides Kitchen Ltd | Hospitality | 2024 |
| Tideydavies Limited | Manufacturing | 2004 |
| Tieferblick Ltd | Administrative & support | 2025 |
| Tihu KU Ltd | Professional & scientific | 2019 |
| TIM Rees Consultancy Limited | Professional & scientific | 2021 |
| Timber & Grey Limited | Professional & scientific | 2022 |
| Time Quest Pembrokeshire Ltd | Education | 2022 |
| TIR a MÔR Festival ST Davids Ltd | Education | 2019 |
| Titan Cleaning Services Limited | Administrative & support | 2025 |
| TJ (Wales) Limited | Hospitality | 2013 |
| TJB Electricals Ltd | Construction | 2015 |
| TK Sharp GAS Ltd | Wholesale & retail | 2020 |
| TLC Design Ltd | Other services | 2008 |
| Toby Hancock Agri Ltd | Administrative & support | 2025 |
| Tocyn Ltd | Information & communication | 2026 |
| TOM Smith (Parts) Limited | Wholesale & retail | 2002 |
| Tomlin Investment Properties Ltd | Real estate | 2025 |
| Tommy France Carpentry Limited | Construction | 2017 |
| Tool Trader Direct Limited | Wholesale & retail | 2009 |
| Torem Ltd | Extraterritorial | 2024 |
| Torun Ltd | Other services | 2022 |
| Torus River Ltd | Extraterritorial | 2025 |
| Total Building & Property Services Ltd | Construction | 2024 |
| Totally Cool Limited | Health & social care | 1998 |
| Touchdown International Ltd | Administrative & support | 1973 |
| Towy Finance Limited | Administrative & support | 1953 |
| Trader 76 Ltd. | Wholesale & retail | 2012 |
| Transition BRO Gwaun Ltd | Health & social care | 2011 |
| Transition Community Ventures Limited | Financial services | 2014 |
| Trearched Holdings Limited | Financial services | 2019 |
| Trecorras Farm Ltd | Construction | 2006 |
| Tree of Life Spirit Ltd | Extraterritorial | 2021 |
| Treedwellers Development Company Limited | Administrative & support | 2021 |
| Treedwellers Limited | Hospitality | 2020 |
| Treedwellers Operations Company Limited | Administrative & support | 2021 |
| Treedwellers Property Company Limited | Administrative & support | 2021 |
| Treeworks (West Wales) Ltd | Agriculture & fishing | 2002 |
| Trefacwn Cottages Limited | Hospitality | 2025 |
| Trefgarn Owen Caravan Park Ltd | Hospitality | 2007 |
| Tregwynt Estate Ltd | Professional & scientific | 1997 |
| Tregwynt Ltd | Real estate | 2022 |
| Trehale Farm Limited | Agriculture & fishing | 2016 |
| Treibhaus Ltd | Extraterritorial | 2025 |
| Trellyn Limited | Hospitality | 2009 |
| TRF Motorsport Ltd | Arts & recreation | 2025 |
| TRI Balance Ltd | Professional & scientific | 2024 |
| Tri-Goat Ltd | Construction | 2025 |
| Trier Contracting Ltd | Other services | 2023 |
| Tritos Ltd | Other services | 2021 |
| Trizaro Limited | Wholesale & retail | 2012 |
| Trovato Ltd | Administrative & support | 2023 |
| Tru-Plas Trade Limited | Construction | 2022 |
| True Live Ltd | Administrative & support | 2023 |
| Truefit Ltd | Extraterritorial | 2025 |
| Truplas Limited | Construction | 1991 |
| Truth Live Ltd | Extraterritorial | 2021 |
| Tsib Limited | Information & communication | 1995 |
| Tulam Ltd | Other services | 2014 |
| Tunkasila Ltd | Administrative & support | 2024 |
| Tunwest Ltd | Administrative & support | 2014 |
| Turmeric-Pic Limited | Wholesale & retail | 2025 |
| Turning Point Child Therapy Ltd | Education | 2024 |
| TW Fibre Optics Ltd | Information & communication | 2022 |
| TW Inspection Contracts Ltd | Construction | 2014 |
| Twaite UK Limited | Real estate | 2011 |
| Twistedpair Kustom Creations Ltd | Manufacturing | 2020 |
| Twistedpair Wiring Solutions Ltd | Manufacturing | 2012 |
| Twister Investments LLP | | 2018 |
| Twlcy Limited | Agriculture & fishing | 2024 |
| TY Cegin CIC | Wholesale & retail | 2025 |
| TY Gwyn Holdings (Pembrokeshire) Limited | Financial services | 2024 |
| TY Gwynne Limited | Real estate | 2021 |
| TYF Adventure Ltd | Administrative & support | 2023 |
| TYF Cafe Ltd | Hospitality | 2024 |
| Tygrug Glamping Limited | Hospitality | 2021 |
| Tyson-Lloyd Developments (Wales) Ltd | Construction | 2018 |
| TŶ Hiraeth Ltd | Real estate | 2024 |
| UK Roman Ltd | Agriculture & fishing | 2026 |
| Uktorg LP | | 2018 |
| Unearthed Festival Limited | Arts & recreation | 2015 |
| Unearthed Greener Events Limited | Hospitality | 2022 |
| Unico Investment Holdings Ltd | Financial services | 2024 |
| Unico Media Ltd | Information & communication | 2023 |
| Unico Vita Ltd | Administrative & support | 2023 |
| Unicy Ltd | Other services | 2019 |
| Uniknow Company Ltd | Information & communication | 2025 |
| Unireg Ltd | Administrative & support | 2017 |
| Unison Homes Ltd. | Real estate | 2014 |
| Unitrag Ltd | Other services | 2021 |
| Universal Safety and Environmental Consultants Ltd | Professional & scientific | 1996 |
| Unlimited Possibility Ltd | Extraterritorial | 2024 |
| Unsunghero Limited | Wholesale & retail | 2021 |
| Utility Concepts Business Solutions Ltd Limited | Administrative & support | 2025 |
| Uxia Fishing Limited | Agriculture & fishing | 2003 |
| Van NES Business Services Ltd | Construction | 2002 |
| Vaughan Creations Limited | Wholesale & retail | 2012 |
| Vaughans Radio Holdings Ltd | Financial services | 2026 |