| Tuksy Lettings Limited | Real estate | 2022 |
| Tuksy Rentals Limited | Real estate | 2022 |
| Tunley Environmental Management Services Ltd | Professional & scientific | 2023 |
| Tunnelbuilder Ltd | Information & communication | 2002 |
| Tupcu Limited | Hospitality | 2019 |
| Turf Barn Diner Limited | Hospitality | 2025 |
| Turks Head Properties Limited | Real estate | 2025 |
| Turn-Key Properties (SW) Ltd | Real estate | 2025 |
| Turner Fluidpower Limited | Transport & logistics | 2002 |
| Turner Hydraulic Filtration Systems Limited | Manufacturing | 2020 |
| Turner Hydraulic Site Services Limited | Manufacturing | 2008 |
| TUT (Bridgend) Ltd | Hospitality | 2018 |
| Twelv Health Ltd | Professional & scientific | 2024 |
| Twelve-Turtles Trading Company Ltd | Wholesale & retail | 2019 |
| Twende Ltd | Information & communication | 2026 |
| TWENTY3 Hospitality Limited | Hospitality | 2022 |
| Twill & Tidy Ltd | Administrative & support | 2025 |
| Twin Route Limited | Real estate | 2025 |
| Twincess Bakes Limited | Manufacturing | 2025 |
| Twinz Fishbar Ltd | Hospitality | 2026 |
| TWK Gym Ltd | Arts & recreation | 2023 |
| Two Brothers (NPT) Ltd | Hospitality | 2019 |
| Two Simmering Pans Limited | Hospitality | 2015 |
| Two Sisters Hotels Limited | Hospitality | 2015 |
| TWO25 Luxe Events Ltd | Hospitality | 2026 |
| Twoclicksout Ltd | Wholesale & retail | 2025 |
| Twyn Oaks Property Management Limited | Households | 2001 |
| Twyne Homes Ltd | Real estate | 2023 |
| TY Capten Barn Limited | Hospitality | 2023 |
| TY Carreg Mawr Holdings Limited | Financial services | 2020 |
| TY Developments Ltd | Real estate | 2024 |
| TY Isaf Farm Ltd | Agriculture & fishing | 2021 |
| TY Llew Management Limited | Real estate | 2019 |
| TY Parc Construction Limited | Construction | 2022 |
| TY Property Sourcing Limited | Real estate | 2019 |
| TY SA Investments Ltd | Real estate | 2022 |
| TY SA Ltd | Real estate | 2019 |
| TY Vehicle Logistics Limited | Other services | 2024 |
| Ty-Gwyn Estates Limited | Real estate | 2001 |
| TYC Influence Ltd | Professional & scientific | 2026 |
| Tylex Limited | Construction | 2013 |
| Tyme by Carl Cleghorn Ltd | Hospitality | 2025 |
| Tymor Y Ddraig Limited | Administrative & support | 2024 |
| Tyre Dynamics Limited | Wholesale & retail | 2013 |
| Tyre Expert Ltd | Wholesale & retail | 2023 |
| Tyrone Power Ltd | Extraterritorial | 2026 |
| Tythus Ltd | Information & communication | 2013 |
| TŶ Awen CYF | Wholesale & retail | 2025 |
| TŶ Green Ltd. | Construction | 2022 |
| U.K. Commercial & Residential Lettings Limited | Real estate | 2004 |
| UAJ Limited | Information & communication | 2025 |
| Uascorp Ltd | Manufacturing | 2023 |
| UD Auto Sales Ltd | Wholesale & retail | 2019 |
| Uddin EC Ltd | Wholesale & retail | 2025 |
| Uddin's (Europe) Limited | Arts & recreation | 2017 |
| UDK 2018 Limited | Information & communication | 2018 |
| UHY Hacker Young (Bristol) Limited | Professional & scientific | 2011 |
| UK & IE Flora Group Limited | Manufacturing | 1997 |
| UK Car Trader Ltd | Wholesale & retail | 2019 |
| UK Daffodils Limited | Wholesale & retail | 2020 |
| UK Erectors Ltd | Other services | 2024 |
| UK Fest X Ltd | Arts & recreation | 2026 |
| UK Fleet Manager Limited | Extraterritorial | 2009 |
| UK Gymnastics Association Limited | Other services | 2002 |
| UK Haoyu Metal Products Co., Ltd | Wholesale & retail | 2020 |
| UK Local Properties Ltd | Real estate | 2023 |
| UK MAX International Limited | Administrative & support | 2008 |
| UK Modern-Moves Limited | Real estate | 2025 |
| UK Online Seller Ltd | Information & communication | 2016 |
| UK Recycling Centres Limited | Water & waste | 2022 |
| UK Retail Construction Limited | Construction | 2020 |
| UK Tyre Trader Limited | Wholesale & retail | 2025 |
| Ukksp Limited | Transport & logistics | 2025 |
| Ukmi Finance Ltd | Financial services | 2024 |
| Ulkr Limited | Other services | 2025 |
| Ullyses Holdings Limited | Financial services | 2021 |
| Ullyses Ltd | Construction | 2002 |
| Ullyses Properties Ltd | Real estate | 2022 |
| Ultimate Electrical Ltd | Construction | 2009 |
| Ultimate Sacrifice Ltd | Extraterritorial | 2018 |
| Ultimate Solutions (South Wales) Limited | Construction | 2018 |
| Ultimate Taxis Limited | Administrative & support | 2008 |
| Ultra Care Community Solutions CIC | Health & social care | 2026 |
| Ultra Care Health Professionals Ltd | Administrative & support | 2018 |
| Ultra Cryo Cleaning Ltd | Wholesale & retail | 2025 |
| Ultra Education Recruitment Ltd | Administrative & support | 2025 |
| Ultra Stores Premier Ltd | Wholesale & retail | 2013 |
| Ultrasource Ltd | Information & communication | 2019 |
| ULY Transport Ltd | Transport & logistics | 2017 |
| UM Property Limited | Real estate | 2026 |
| Umar and Musa Ltd | Hospitality | 2025 |
| Umbra Velo Group Ltd | Wholesale & retail | 2026 |
| Umes Services Limited | Health & social care | 2024 |
| UN Mahmood Ltd | Health & social care | 2026 |
| Uncle Boutique and Logistic Limited | Health & social care | 2018 |
| Undecided Project Limited | Wholesale & retail | 2025 |
| Underground Service Engineering Ltd | Water & waste | 2021 |
| Undermark Ltd | Wholesale & retail | 2025 |
| UNI Developments Ltd | Real estate | 2021 |
| Unikk Ltd | Construction | 2019 |