| Thefactorymedia Ltd | Wholesale & retail | 2018 |
| Thefinnacompany Ltd | Information & communication | 2022 |
| Theironcollectiveuk Limited | Arts & recreation | 2025 |
| Themakeupaisle Ltd | Wholesale & retail | 2016 |
| THEMIS2020 Ltd | Professional & scientific | 2020 |
| Themsley Ltd | Administrative & support | 2012 |
| Thenewleafcompany Ltd | Administrative & support | 2006 |
| Thenonexec Limited | Professional & scientific | 2009 |
| Theprimetechno Ltd | Wholesale & retail | 2023 |
| Thepromise Ltd | Wholesale & retail | 2025 |
| Thepurehealth Ltd | Wholesale & retail | 2025 |
| Thera Investments Limited | Real estate | 1963 |
| There SHE Glows Beauty & Academy Ltd | Education | 2025 |
| Thermal Group Limited | Construction | 2013 |
| Thermalsavings Ltd | Professional & scientific | 2015 |
| Thermsolution Limited | Wholesale & retail | 2024 |
| Thescrummaster.Co.Uk Ltd | Information & communication | 2022 |
| Thingstream Limited | Information & communication | 2018 |
| Think Create Digital Ltd | Information & communication | 2018 |
| Think Green Developments Limited | Extraterritorial | 2017 |
| Think Research Limited | Professional & scientific | 2004 |
| Think Tiger Ltd | Information & communication | 2016 |
| Thinking Class Limited | Professional & scientific | 2025 |
| Third ACT Limited | Professional & scientific | 2024 |
| Third Realm Limited | Administrative & support | 2013 |
| Third Square Cowork Ltd | Real estate | 2024 |
| This Big World Ltd | Wholesale & retail | 2026 |
| This Brand Works Limited | Professional & scientific | 2021 |
| This IS Abcd Limited | Information & communication | 2011 |
| This IS Sandbanks Ltd | Professional & scientific | 2022 |
| This IS Squeeze Ltd | Information & communication | 2021 |
| THL Superyachts Limited | Other services | 2017 |
| Thomas Boyce Events Ltd | Hospitality | 2022 |
| Thomas Matthew Kitchens Ltd | Manufacturing | 2018 |
| Thompson Composite Mouldings Limited | Manufacturing | 2011 |
| Thompson F I T Limited | Real estate | 2017 |
| Thompson Logistics Consulting Ltd | Other services | 2013 |
| Thompson's Catering Ltd | Hospitality | 2023 |
| Thomson Binaris Ltd | Information & communication | 2012 |
| Thor Electrical and Data Services Limited | Construction | 1998 |
| Thoriumcube Holdings Limited | Financial services | 2023 |
| Thoriumcube Operations Ltd | Information & communication | 2022 |
| Thorn Spire Games Ltd | Information & communication | 2023 |
| Thorncombe Recruitment Ltd | Administrative & support | 2025 |
| Thornes Surveyors Limited | Professional & scientific | 2013 |
| Thornlow Heights Ltd | Households | 2022 |
| Thornwick Studios Limited | Information & communication | 2025 |
| Thornycroft Limited | Wholesale & retail | 2011 |
| Thoughtful Partner Limited | Other services | 2025 |
| Thread Labs Group Limited | Wholesale & retail | 2026 |
| Threads of Meaning Ltd | Manufacturing | 2025 |
| Threadsovereign Ltd | Information & communication | 2026 |
| Three Circle Tech Ltd | Information & communication | 2024 |
| Three Counties Motorhomes Limited | Wholesale & retail | 2008 |
| Three Kings Properties Limited | Extraterritorial | 2024 |
| Three VEE Limited | Information & communication | 1987 |
| THREE60 Consulting Solutions Limited | Administrative & support | 2015 |
| Thriftwood Holdings Limited | Extraterritorial | 2002 |
| Thriving Daily Ltd | Professional & scientific | 2022 |
| Through Leaves Limited | Financial services | 2021 |
| Thrudark Limited | Wholesale & retail | 2016 |
| Thrust Medical Services Limited | Health & social care | 2014 |
| THS Fight Gear Ltd | Wholesale & retail | 2023 |
| Thunderholt Holdings Limited | Financial services | 2020 |
| Thundersports (Sports Breaks) LLP | | 2010 |
| Thyme & Shine Limited | Other services | 2023 |
| Thymeforyou Ltd | Professional & scientific | 2026 |
| Thymos Ltd | Information & communication | 2023 |
| Tiac Technical Ltd | Administrative & support | 2013 |
| Tiago Almeida Ltd | Information & communication | 2019 |
| Tibbs Accounting Services Ltd | Professional & scientific | 2011 |
| Tickethive Ltd | Wholesale & retail | 2026 |
| Tidal Studios Design Web Print Limited | Information & communication | 2010 |
| Tidemains Limited | Real estate | 1979 |
| Tides Marine International Limited | Manufacturing | 2002 |
| Tidestar (Bournemouth) Limited | Construction | 2007 |
| Tideward Limited | Wholesale & retail | 2026 |
| Tidey Sailing Ltd | Arts & recreation | 2022 |
| Tidy Touch Companion Limited | Water & waste | 2024 |
| Tier 2 Ipmt Limited | Professional & scientific | 2017 |
| Tiffany Brazil Limited | Wholesale & retail | 2025 |
| Tiger Property Finance Ltd | Financial services | 2015 |
| Tigerrun Productions Limited | Information & communication | 2017 |
| Tigoos Mktg Limited | Wholesale & retail | 2025 |
| Tijarao Ltd | Wholesale & retail | 2025 |
| Tik.Travel Ltd | Wholesale & retail | 2023 |
| Tilboscrafts Ltd | Wholesale & retail | 2025 |
| Tilk International Ltd | Education | 2024 |
| Tilsed (Poole) Limited | Construction | 2013 |
| Tilsed Towers Fitness TA Muscle Revive Ltd | Health & social care | 2025 |
| Tilsed Towers Properties 16LR-F2 Ltd | Real estate | 2025 |
| Tilsed Towers Tech Ltd | Information & communication | 2024 |
| Tima Cardiology Ltd | Health & social care | 2025 |
| Timbers Group Ltd | Financial services | 2021 |
| Timbers Properties Ltd | Real estate | 2022 |
| Timbers Studio Ltd | Information & communication | 2020 |
| Time and Data Systems International Limited | Manufacturing | 1981 |
| Timeflux Limited | Information & communication | 2025 |
| Timeless Engineering Ltd | Manufacturing | 2016 |
| Times Supply Co. Ltd | Manufacturing | 2022 |