| Taylor and Melling Holdings Limited | Financial services | 2025 |
| Taylor Catering Ltd | Hospitality | 2025 |
| Taylor Grey Associates Ltd | Real estate | 2019 |
| Taylors Cross Wind Energy Ltd | Energy | 2013 |
| Taûros Building Services Limited | Construction | 2025 |
| TB Bridal Ltd | Wholesale & retail | 2018 |
| TB Property (Plymouth) Limited | Real estate | 2016 |
| TB Property Advisory Limited | Professional & scientific | 2017 |
| TB Property Developments (Plymouth) Limited | Construction | 2016 |
| TB Property Investments (Plymouth) Limited | Real estate | 2017 |
| TBCG2 Ltd | Financial services | 2023 |
| TBE Academy Limited | Education | 2025 |
| Tbhb Holdings Ltd | Financial services | 2023 |
| Tbtb C.I.C. | Education | 2014 |
| TC Dent Ltd | Health & social care | 2021 |
| TC Motorsport Ltd | Wholesale & retail | 2018 |
| TC13 Ltd | Professional & scientific | 2025 |
| TCH Management Consultancy Limited | Administrative & support | 2025 |
| Tcmx Limited | Information & communication | 2025 |
| TCS (Swansea) Ltd | Administrative & support | 2025 |
| TCS Plant Hire Limited | Administrative & support | 2009 |
| TD Heating Solutions Ltd | Construction | 2026 |
| Tdma Ltd | Arts & recreation | 2020 |
| Teach Learn Create Limited | Education | 2013 |
| Teaching Autism Ltd | Education | 2020 |
| Teakcrest Limited | Professional & scientific | 2012 |
| Team Price Personal Training Ltd | Other services | 2023 |
| Team Price Sports Therapy Limited | Arts & recreation | 2026 |
| Team Tours Direct Ltd | Arts & recreation | 2004 |
| Teamforce UK Limited | Arts & recreation | 2005 |
| Teamgranitefitness Ltd | Health & social care | 2024 |
| Teammi Ltd | Professional & scientific | 2023 |
| Teamnft Limited | Arts & recreation | 2023 |
| Teamsteady Limited | Professional & scientific | 1992 |
| Teamz Sportswear Ltd | Manufacturing | 2012 |
| Tear Properties Limited | Real estate | 2023 |
| Tear Scaffolding Specialists Limited | Construction | 2020 |
| TEC Electrical Ltd | Construction | 2025 |
| Techdrobe Ltd | Information & communication | 2020 |
| Techlan Limited | Professional & scientific | 2009 |
| Technical Difficulties Limited | Wholesale & retail | 2019 |
| Technical Support Services Cardiff Limited | Financial services | 2017 |
| Technoplus Services Limited | | 2001 |
| Teck Property Limited | Real estate | 2019 |
| Tectonics Drilling Services Ltd | Construction | 2014 |
| Tectra Property Ltd | Real estate | 2026 |
| TED Hearing Group Limited | Professional & scientific | 2021 |
| TED Rees Financial Services Ltd | Financial services | 2014 |
| Teddy and Belle Limited | Wholesale & retail | 2026 |
| Tedex Carpentry Ltd | Extraterritorial | 2022 |
| Tedex Construction Ltd | Construction | 2024 |
| Teepee Tastic Ltd | Arts & recreation | 2019 |
| Tegid Road Limited | Real estate | 2024 |
| Teilo Homes Limited | Real estate | 2021 |
| Teilo’S Tots CIC | Health & social care | 2025 |
| Teknikka Limited | Manufacturing | 2009 |
| Telecom Expert Solutions Ltd | Information & communication | 2024 |
| Teledu Annibynwyr Cymru Cyfyngedig | Extraterritorial | 2010 |
| Teledu Telesgop CYF | Arts & recreation | 1993 |
| Telesgop Masnachol CYF | Financial services | 2025 |
| Telesgop Media CYF | Professional & scientific | 2018 |
| Telexi Rides Ltd | Transport & logistics | 2025 |
| Tellus Industries Ltd | Agriculture & fishing | 2020 |
| Telmessos Ltd | Construction | 2018 |
| Teln Ltd | Professional & scientific | 2019 |
| Tempa Studios Limited | Wholesale & retail | 2026 |
| Temple Dynamic Limited | Information & communication | 2014 |
| Tempus Novum Property # 127 G821LE Ltd | Real estate | 2022 |
| Tempus Novum Property # 68-71 CF374DA Ltd | Real estate | 2021 |
| Tempus Novum Property Ltd | Real estate | 2020 |
| Tempus Novum Property Trading Ltd | Real estate | 2023 |
| Temtec Services Ltd | Manufacturing | 2015 |
| TEN Thousand YEN Ltd | Information & communication | 2013 |
| TEN:15 Ltd | Professional & scientific | 2021 |
| Tender Concepts Limited | Professional & scientific | 2024 |
| Teneo Properties Limited | Real estate | 2015 |
| Tennis Swansea 365 | Arts & recreation | 2010 |
| Teqnecia Ltd | Information & communication | 2022 |
| Tequila's Limited | Hospitality | 1996 |
| Teraquad Limited | Professional & scientific | 2009 |
| Terdonkin Investments Limited | Extraterritorial | 1959 |
| Terekamortgagebrokers Ltd | Financial services | 2024 |
| Terra Electrical Solutions Limited | Construction | 2022 |
| Terra Firma Today Limited | Households | 2018 |
| Terry Jones CQS Limited | Professional & scientific | 2005 |
| Terwill Properties Limited | Real estate | 2017 |
| Tesni Ltd | Health & social care | 2018 |
| Tess Construction Ltd | Construction | 2024 |
| Tetrik Limited | Manufacturing | 2025 |
| Tevid Properties Ltd | Real estate | 2026 |
| TF Gear Limited | Wholesale & retail | 2021 |
| TF Medics Care Limited | Health & social care | 2024 |
| TG Carpentry and Construction Ltd | Construction | 2021 |
| TGC Collectables Limited | Wholesale & retail | 2025 |
| TGD Services Ltd | Construction | 2020 |
| Tghc Group Ltd | Construction | 2024 |
| Tgold Serial Concept Limited | Transport & logistics | 2024 |
| TH Property Assets & Management Limited | Real estate | 2023 |
| Thai Bach Express Limited | Hospitality | 2024 |
| Thai Bach Limited | Hospitality | 2014 |