| Tile Rack (Wales) Limited | Wholesale & retail | 2004 |
| Tileya Ltd | Hospitality | 2023 |
| Tilleys Jewellers Limited | Wholesale & retail | 2013 |
| Tilly Invest Ltd | Real estate | 2024 |
| TIM Johns Limited | Financial services | 2015 |
| TIM Lynch Property Maintenance Ltd | Administrative & support | 2020 |
| TIM Taylor & Co Ltd | Professional & scientific | 2008 |
| TIM Whitford IMA Limited | Financial services | 2022 |
| Tim's Sushi Limited | Hospitality | 2023 |
| Tim-Tec Limited | Construction | 2023 |
| Timas Hair and Beauty Ltd | Wholesale & retail | 2024 |
| Timba Limited | Manufacturing | 2012 |
| Timber Harvesting (Neath) Limited | Agriculture & fishing | 2019 |
| Timberjoinery Ltd | Manufacturing | 2019 |
| Time Designers Limited | Information & communication | 2012 |
| Timeless Trinkets & Repair Ltd | Wholesale & retail | 2025 |
| Timple Ltd | Real estate | 2018 |
| Tina's Jive Ltd | Wholesale & retail | 2023 |
| Tinbat Global Commmerce UK Ltd | Wholesale & retail | 2026 |
| Tinmasters Group Limited | Financial services | 2010 |
| Tinmasters Limited | Manufacturing | 2010 |
| Tinmasters Swansea Limited | Manufacturing | 1923 |
| Tinpac Ltd | Manufacturing | 2009 |
| Tintac Limited | Administrative & support | 2009 |
| Tinworks Brewing Company Ltd. | Manufacturing | 2017 |
| Tiny Beginnings Limited | Education | 2005 |
| Tiny Swans: Growing Together CIC | Health & social care | 2026 |
| Tiny Toes Ballet Limited | Education | 2012 |
| TIP Top Environmental Limited | Administrative & support | 2024 |
| TIP Top Toilets Group Limited | Administrative & support | 2024 |
| Tipsy Neath Limited | Hospitality | 2025 |
| TIR Canol Holdings Limited | Real estate | 2000 |
| Tirano Limited | Real estate | 1997 |
| Tircoed Village Trust | Real estate | 1995 |
| Tirwedd Sustainable Garden and Tree Services LLP | | 2023 |
| Titan Health Coaching Limited | Health & social care | 2023 |
| Titan Pharma Ltd | Health & social care | 2022 |
| Titan Propco Limited | Households | 2023 |
| Titan Roofers Ltd | Construction | 2024 |
| Titan Strength and Conditioning Ltd | Arts & recreation | 2019 |
| Titan Vehicle Locks Ltd | Administrative & support | 2021 |
| Titw Tomos LAS Limited | Wholesale & retail | 2026 |
| TJ Accountancy Ltd | Professional & scientific | 2008 |
| TJ Assessment & Consultancy Limited | Administrative & support | 2013 |
| TJ Care Solutions Ltd | Health & social care | 2015 |
| TJ Cycleworx Ltd | Wholesale & retail | 2026 |
| TJH Installations Ltd | Construction | 2025 |
| Tjmc Properties Limited | Construction | 2020 |
| TJO Properties Limited | Real estate | 2025 |
| Tjycl Limited | Real estate | 2025 |
| TK Asset Mgmt Ltd | Real estate | 2022 |
| TK2 Investments Limited | Real estate | 2014 |
| TKF Properties Limited | Real estate | 2024 |
| TKI Solutions Limited | Information & communication | 2025 |
| TKN Solutions Ltd | Professional & scientific | 2025 |
| TKR Management Ltd | Real estate | 2015 |
| TKS Property Ltd | Real estate | 2024 |
| TM Inc (Insulation & Consulting) Ltd | Other services | 2016 |
| TM9 Ltd | Information & communication | 2024 |
| TMA Holiday Lets Limited | Real estate | 2022 |
| TMJ EOD Consultancy Services Ltd | Construction | 2024 |
| TMK Blade Runner Services Ltd | Professional & scientific | 2023 |
| TMM2 Limited | Health & social care | 2026 |
| TMT Trading Ltd | Wholesale & retail | 2025 |
| TNC Recruitment Solutions Limited | Administrative & support | 2015 |
| TNG Evaluations Ltd. | Transport & logistics | 2026 |
| TNJ Catering Ltd | Hospitality | 2024 |
| Tnlocks Ltd | Real estate | 2025 |
| TNS Tharsan Property Ltd | Wholesale & retail | 2025 |
| TNT Elevate Ltd | Wholesale & retail | 2023 |
| TO and FRO Here WE Go Ltd | Transport & logistics | 2017 |
| TO FLY for a Delivery GUY Limited | Transport & logistics | 2024 |
| Toast (Mail Order) Limited | Wholesale & retail | 1997 |
| Toasted Coffee Shop Ltd | Hospitality | 2024 |
| Toby Delivers Ltd | Wholesale & retail | 2025 |
| Toby Grace Properties Limited | Real estate | 2022 |
| Tocg UK Limited | Financial services | 2021 |
| Tocs Fabrications Limited | Manufacturing | 2014 |
| Tocs Solutions Limited | Construction | 2018 |
| Todd 10 Sports Limited | Wholesale & retail | 2024 |
| Toddler Sense Swansea East Ltd | Education | 2023 |
| Toddy Tours Ltd | Transport & logistics | 2025 |
| Toft Global Limited | Wholesale & retail | 2017 |
| Toft Holdings Ltd | Financial services | 2016 |
| Together Stronger (South Wales) Ltd | Health & social care | 2021 |
| TOM Barker Cinematography Ltd | Information & communication | 2019 |
| TOM Edmunds Real Estate Ltd | Real estate | 2025 |
| TOM Graham Maintenance Ltd | Construction | 2026 |
| TOM Harty (Meats) Company Limited | | 1976 |
| TOM Jenkins Electrical Ltd | Construction | 2019 |
| TOM RAX Ltd | Transport & logistics | 2026 |
| TOM Short Ltd | Information & communication | 2022 |
| Tomos Dafydd Hopkins Limited | Extraterritorial | 2025 |
| Tomos Watkin Brewery (Wales) Limited | Extraterritorial | 2016 |
| Tomos Watkin Brewery Ltd | Extraterritorial | 2016 |
| Tonara Limited | Real estate | 2011 |
| Tondo Design & Build Limited | Construction | 2018 |
| Tone Photographic Ltd | Manufacturing | 2025 |
| Tong JIN Ltd | Hospitality | 2015 |
| Toni WIL International Limited | Real estate | 1995 |