| Thorney Investments Ltd | Financial services | 2025 |
| Thornhill Procurement Limited | Professional & scientific | 2018 |
| Thornley Software Limited | Information & communication | 2007 |
| Thorogood's Properties Ltd | Real estate | 2026 |
| Thorpe & SON Limited | Construction | 2011 |
| Thorpe Property Suffolk Limited | Real estate | 2024 |
| Thorpeness Property Ltd | Real estate | 2025 |
| Those Little Details Limited | Extraterritorial | 2014 |
| Thoughtstream Consulting Limited | Professional & scientific | 2014 |
| THP Bookkeeping Ltd | Professional & scientific | 2025 |
| Threads for ALL Ltd | Wholesale & retail | 2024 |
| Three C'S Travel Ltd | Transport & logistics | 2006 |
| Three IS Company Limited | Other services | 2001 |
| Three Monkeys Marketing Co Ltd | Administrative & support | 2017 |
| Three Rivers Holdings Limited | Agriculture & fishing | 2015 |
| Three Rivers Wealth Management Ltd | Professional & scientific | 2025 |
| Threepenny Convenience Store Ltd | Wholesale & retail | 2023 |
| Threshold Solutions Ltd | Construction | 2003 |
| Thrive Business Enterprise Limited | Real estate | 2025 |
| Thrive Safe Limited | Education | 2021 |
| THT Enterprises Ltd | Real estate | 2022 |
| Thumbdance Media Ltd | Professional & scientific | 2025 |
| Thunderbolt FX Ltd | Wholesale & retail | 2023 |
| Thurktech Limited | Information & communication | 2016 |
| Thurst Hurdle Ltd | Hospitality | 2019 |
| Thurston Olive Limited | Wholesale & retail | 2013 |
| Thurston Park (Thurston) Management Company Limited | Households | 2020 |
| Thurston Surveying Services Limited | Construction | 2009 |
| Thurton Ethical Investments Limited | Information & communication | 2010 |
| Thus(Digital) Ltd | Information & communication | 2024 |
| Thuy Tran Nails Limited | Other services | 2019 |
| Thyme Lane Photography Ltd | Professional & scientific | 2013 |
| Tibanna Ltd | Transport & logistics | 2022 |
| Tibooks Ltd | Information & communication | 2022 |
| Ticket I.D UK Limited | Wholesale & retail | 2022 |
| Ticketgun.Com Ltd | Wholesale & retail | 2014 |
| Tide Promotions Limited | Professional & scientific | 2023 |
| Tide Shipping Ltd | Transport & logistics | 2020 |
| Tide Training Ltd | Administrative & support | 2025 |
| Tide Transport Ltd | Transport & logistics | 2021 |
| Tide Warehousing Ltd | Transport & logistics | 2021 |
| Tidea Storage Ltd | Real estate | 2015 |
| TIE Zone Limited | Administrative & support | 2020 |
| Tier 3 Limited | Professional & scientific | 2024 |
| TIG Recruitment Ltd | Real estate | 2015 |
| Tiger Cycles Ltd | Wholesale & retail | 2017 |
| Tiger Cycles UK Ltd | Financial services | 2018 |
| Tiger Stepstone Ltd | Real estate | 2026 |
| Tignosis Limited | Extraterritorial | 1993 |
| Tihuk Limited | Real estate | 2016 |
| Tikoga Investments Limited | Real estate | 2014 |
| Tile & Co Essex Ltd | Professional & scientific | 2023 |
| Tile & Stone Gallery Limited | Extraterritorial | 2003 |
| Tiles Network Ltd | Real estate | 2018 |
| Tilia Ltd | Professional & scientific | 2016 |
| Tilleys Property Services Limited | Construction | 2006 |
| Tillio Automotive Ltd | Wholesale & retail | 2011 |
| Tillow Marine Management Ltd | Professional & scientific | 2024 |
| Tilted Umbrella Services Limited | Professional & scientific | 2024 |
| Timbars Ltd | Real estate | 2019 |
| Timber Field Trading Ltd | Wholesale & retail | 2014 |
| Timber Investments Limited | Financial services | 2023 |
| Timbereist Ltd | Wholesale & retail | 2015 |
| Timberwolf Services Ltd | Administrative & support | 2020 |
| Time 770 Ltd | Administrative & support | 2026 |
| Time Appointments Limited | Administrative & support | 2006 |
| Time Finance Appointments Ltd | Extraterritorial | 2014 |
| Timeco Ltd | Hospitality | 2007 |
| Timeless AI Ltd | Information & communication | 2024 |
| Timeless Group Services Ltd | Financial services | 2021 |
| Timeless INK Beauty Ltd | Other services | 2025 |
| Timeless Princess Limited | Extraterritorial | 2010 |
| Timeless Property Ltd | Construction | 2016 |
| Timeless Recruitment Ltd | Administrative & support | 2020 |
| Timeless Structures Construction Ltd | Construction | 2019 |
| Timeless Suffolk Ltd | Real estate | 2021 |
| Timemet Limited | Extraterritorial | 1990 |
| Times Workshop | Health & social care | 2025 |
| Timmis Carpentry Limited | Construction | 2015 |
| Timnastic ENT Limited | Arts & recreation | 2023 |
| Timothy N. Horne Ltd | Professional & scientific | 2011 |
| Tina Harris Properties Limited | Real estate | 2019 |
| Tina Ipswich Ltd | Wholesale & retail | 2025 |
| Tinana Ltd | Real estate | 2019 |
| Tiny Mites Music and Theatre Productions Ltd | Administrative & support | 2018 |
| Tiny Tots Sensory Ltd | Health & social care | 2026 |
| Tip-N-Lift (UK) Limited | Manufacturing | 1991 |
| Tip-Top (Waste) Limited | Extraterritorial | 1989 |
| Tippers "R" US Limited | Professional & scientific | 1994 |
| Tipplers Garden Ltd | Hospitality | 2022 |
| Titan Brickwork Solutions Ltd | Construction | 2018 |
| Titan Converting Equipment Ltd | Extraterritorial | 2014 |
| Titan Route Ltd | Transport & logistics | 2026 |
| Titash Indian Restaurant Ltd | Hospitality | 2009 |
| Titchmarsh & Goodwin Fine Furniture Limited | Manufacturing | 2016 |
| Tithe Contracts Limited | Construction | 2002 |
| Titlefinal Property Management Limited | Households | 1997 |
| Titmarsh Heating Ltd | Construction | 2025 |
| Tittlehall Trustees Limited | Professional & scientific | 2012 |
| TJB Construction & Landscaping Ltd | Construction | 2025 |