| Trekkers Travel Limited | Transport & logistics | 1997 |
| Tremolo Ventures LLP | | 2024 |
| Trendbox Ltd | Wholesale & retail | 2023 |
| Trenzavion Ltd | Wholesale & retail | 2025 |
| Tresorbydunni Limited | Manufacturing | 2026 |
| Tresure Company Limited | Transport & logistics | 2018 |
| Trev’Ra Limited | Wholesale & retail | 2026 |
| Trias Holdings Ltd | Hospitality | 2020 |
| Tribeca Advisory Limited | Professional & scientific | 2026 |
| Tribus Residential Homes Limited | Health & social care | 2023 |
| Tributary Drinks Ltd | Extraterritorial | 2013 |
| Trident Seals Limited | Wholesale & retail | 2016 |
| Trim Creative Ltd | Education | 2025 |
| Trinity Care Limited | Health & social care | 2025 |
| Trinity Gate Cambridge Management Company Limited | Households | 2021 |
| Trinity Mews (Hotwells) Management Company Limited | Households | 2003 |
| Trinity SYE Medical Consults Limited | Health & social care | 2026 |
| Trinity UK Investment Ltd | Real estate | 2023 |
| Trinityone Services Ltd | Administrative & support | 2023 |
| Trintel UK Ltd | Administrative & support | 2017 |
| Trio Stars Ltd | Transport & logistics | 2022 |
| Triple Air Ltd | Extraterritorial | 2024 |
| Triple Bashy Limited | Administrative & support | 2023 |
| Triple H Limited | Health & social care | 2022 |
| Triple KAY Properties Ltd | Real estate | 2022 |
| Triple M Enterprise Ltd | Wholesale & retail | 2020 |
| Triple Solar Ltd | Construction | 2011 |
| Tripple-J's Afro-European Hair Salon Ltd | Other services | 2024 |
| Triumphant Plus Limited | Health & social care | 2019 |
| Trizone Electrical Services Ltd | Construction | 2023 |
| Troutmoor Limited | Households | 1972 |
| Troylb Ltd | Construction | 2020 |
| TRS Sports Limited | Arts & recreation | 2023 |
| Truck-Lite Co. Limited | Manufacturing | 1948 |
| TRUCK4ALL Ltd | Transport & logistics | 2026 |
| True Rome UK Ltd | Wholesale & retail | 2023 |
| Trueskin Clinic Ltd | Other services | 2025 |
| Trukx Ltd | Transport & logistics | 2022 |
| Trusson Tech Doctor Limited | Other services | 2025 |
| Trust Care Solutions Ltd | Administrative & support | 2015 |
| Trust Equals Limited | Professional & scientific | 2025 |
| Trust Healthcare Solutions Ltd | Administrative & support | 2015 |
| Trust Lika Construct Ltd | Construction | 2015 |
| Trust Technical Services Ltd | Administrative & support | 2016 |
| Trust Troci Construction Ltd | Construction | 2015 |
| Trusted Books Services Limited | Professional & scientific | 2026 |
| Trustfinity Ltd | Financial services | 2016 |
| Trusty Trowels Ltd | Construction | 2017 |
| TSE Power Ltd | Information & communication | 2026 |
| TSF World Limited | Households | 2025 |
| TSJ Mali Limited | Health & social care | 2026 |
| TSO Global Consult Ltd | Health & social care | 2020 |
| TSW Electrics Limited | Professional & scientific | 2016 |
| TT Fires Ltd | Construction | 2010 |
| Ttgd Logistics Ltd | Administrative & support | 2025 |
| TTY Solutions Limited | Administrative & support | 2013 |
| TUBEEZ2 Ltd | Real estate | 2025 |
| Tudor Realty Group Limited | Real estate | 2025 |
| Tudor SA Limited | Construction | 2023 |
| Tudor Shop Ltd | Wholesale & retail | 2019 |
| Tumise Limited | Health & social care | 2026 |
| Tungsten Energy Ltd | Mining & quarrying | 2023 |
| Turanveli Limited | Other services | 2009 |
| Turbo Motorsports Ltd | Wholesale & retail | 2026 |
| Turkish Cuisine Ltd | Hospitality | 2026 |
| Turkish Online Supermarket Limited | Wholesale & retail | 2025 |
| Turner & Associates Ltd | Professional & scientific | 2026 |
| Turner & Sons Electrical Contractors Ltd | Construction | 2021 |
| Turner Interiors Ltd | Construction | 2012 |
| Turquoise Tomato Ltd | Information & communication | 2023 |
| Tuss Properties Limited | Real estate | 2025 |
| Tutorwithnick Ltd | Education | 2025 |
| Twenty Four Shepherds Hill Residents Management Company Limited | Households | 1984 |
| TWENTY/20 Productions Limited | Information & communication | 2020 |
| TWH Developments Ltd | Other services | 2021 |
| Twi-Lite Holdings Ltd | Information & communication | 2026 |
| Twiga Accountants Ltd. | Professional & scientific | 2011 |
| Twin Plumbing and Ventilation Limited | Construction | 2020 |
| Twinvestment Property Limited | Real estate | 2023 |
| Twirlex Link Services Limited | Health & social care | 2026 |
| TWM Bespoke Glazing Ltd | Construction | 2021 |
| Two Doughballs Limited | Hospitality | 2025 |
| Two Roots Properties Ltd | Construction | 2025 |
| Twoclose Ltd | Information & communication | 2025 |
| Twomet Trading Ltd | Arts & recreation | 2007 |
| Twonineone Electrical Contractors Ltd | Construction | 2011 |
| Twyne Limited | Information & communication | 2025 |
| TY Gwyn Gardens Management Company Limited | Households | 2013 |
| Tycole Trading Ltd | Wholesale & retail | 2023 |
| TYE Green Indoor Bowls Club Limited | Arts & recreation | 1972 |
| TYG Services Ltd | Administrative & support | 2020 |
| Tyler Heating Services Ltd | Professional & scientific | 2021 |
| Tyrant Tools Ltd | Wholesale & retail | 2026 |
| Tyre SOS Mobile Tyres Limited | Wholesale & retail | 2025 |
| U.K. Limited | Wholesale & retail | 1988 |
| UAE & UK Education & Medical Services Ltd | Professional & scientific | 2012 |
| Ucane Limited | Health & social care | 2023 |
| Uddin Family Properties Ltd | Real estate | 2016 |
| Udf-Uk Ltd | Education | 2021 |
| Ufedo Limited | Health & social care | 2021 |