| Trustmark Trades Ltd | Information & communication | 2025 |
| Tsdent Limited | Health & social care | 2024 |
| TSG Blue Ltd | Financial services | 2021 |
| TSM Consultancy Ltd | Professional & scientific | 2024 |
| TTA Investments Ltd | Real estate | 2020 |
| Tudor Close Residents Association Limited(The) | Households | 1952 |
| Tudor Homes Henley Limited | Construction | 2017 |
| Tuhin Mahin Properties Limited | Real estate | 2021 |
| Tuin Design Limited | Professional & scientific | 2021 |
| Tunada Ltd | Hospitality | 2020 |
| Tupo Properties Ltd | Real estate | 2023 |
| Turfex Ltd | Information & communication | 2026 |
| Turhan Ltd | Other services | 2020 |
| Turville & Co Limited | Health & social care | 2019 |
| Turweston Solar Farm Limited | Energy | 2013 |
| Tusker Ridge Ltd | Real estate | 2026 |
| Tutor Room Ltd | Education | 2021 |
| Tutorist Limited | Education | 2023 |
| TV Works Limited | Professional & scientific | 2015 |
| TW Biometrics Limited | Professional & scientific | 2025 |
| Twelve Construction Ltd | Construction | 2025 |
| Twelve Medina Villas (Hove) Limited | Households | 1992 |
| TWELVE33 Limited | Information & communication | 2024 |
| Twenty Medina Villas Ltd | Households | 2021 |
| Twenty Nine Property Management Services Limited | Households | 2024 |
| Twenty One Lansdowne Street Limited | Extraterritorial | 1981 |
| Twenty Plus Seven Limited | Information & communication | 2023 |
| Twenty-Four Adelaide Crescent (Hove) Limited | Real estate | 1989 |
| Twenty-Two Third Avenue (Hove) Limited | Households | 2008 |
| Twentyonedental Clinic Limited | Health & social care | 2014 |
| Twentywines Limited | Administrative & support | 2012 |
| Twilight Vision Music Limited | Information & communication | 2025 |
| Twin Resources Group Ltd | Administrative & support | 2018 |
| Twirl (Hove) Limited | Information & communication | 2016 |
| Twit Twoo Television Limited | Information & communication | 2015 |
| Two Blue Dogs Limited | Administrative & support | 2012 |
| Two Group Theory Ltd | Information & communication | 2022 |
| Two Medina Terrace Property Management Limited | Real estate | 2010 |
| Two Second Avenue Limited | Households | 2003 |
| Two Views Consulting Ltd | Professional & scientific | 2025 |
| TWP Wealth Limited | Financial services | 2011 |
| Tyde Consulting Ltd | Information & communication | 2025 |
| Tydwell Limited | Construction | 2006 |
| Tygres Properties Limited | Real estate | 2023 |
| Tyre Express (Hove) Limited | Wholesale & retail | 2004 |
| Tyres 4U Sussex Ltd | Wholesale & retail | 2026 |
| Tyrrell & Gill Solicitors Limited | Professional & scientific | 2009 |
| Tyto Sustainability Ltd | Professional & scientific | 2025 |
| Ubique Invest Ltd | Professional & scientific | 2022 |
| Ubiquitous Decor Ltd | Construction | 2020 |
| Udigital (Holdings) Ltd. | Professional & scientific | 2001 |
| Udigital Ltd | Administrative & support | 2012 |
| UDR Properties Limited | Administrative & support | 2018 |
| UID Collective Ltd | Hospitality | 2025 |
| UK Asset Management Limited | Real estate | 2011 |
| UK Business Clinic Limited | Professional & scientific | 2021 |
| UK Callnet Network Ltd | Information & communication | 2005 |
| UK E Tutoring Ltd | Education | 2023 |
| UK EMR Trading Ltd | Administrative & support | 2021 |
| UK Euro Logistics Ltd | Construction | 2017 |
| UK HMA Accessories Ltd | Administrative & support | 2015 |
| UK International Education Alliance Limited | Education | 2001 |
| UK Lounge Grills Ltd | Hospitality | 2025 |
| UK Market Ltd | Energy | 2014 |
| UK Racing for Profit Ltd | Administrative & support | 2018 |
| UK Schooling Global Education Ltd | Education | 2026 |
| UK Schooling Ltd | Other services | 2015 |
| UK Services Today Ltd | Professional & scientific | 2017 |
| UK Study Tours Limited | Administrative & support | 2009 |
| UK Study.Com Limited | Administrative & support | 2002 |
| Uk>Speed Ratings Ltd | Arts & recreation | 2007 |
| Ukavco Limited | Transport & logistics | 2016 |
| Ukitach Ltd | Wholesale & retail | 2020 |
| UKQ AA Limited | Arts & recreation | 2025 |
| Ukraine International Events CIC | Arts & recreation | 2023 |
| Uksams Ltd | Other services | 2016 |
| Ulidays Ltd | Hospitality | 2023 |
| Ultra Tooling Limited | Wholesale & retail | 2026 |
| Ultragood Consultancy Limited | Health & social care | 2023 |
| Umbrella Bookkeeping Limited | Professional & scientific | 2015 |
| Uncle Sams Hamburger Express Limited | Hospitality | 1982 |
| Underground Gym Limited | Arts & recreation | 2014 |
| Unicorn Financial Ltd | Financial services | 2017 |
| Unicorn Strike Force Ltd | Information & communication | 2021 |
| Union Bespoke Group Ltd | Manufacturing | 2025 |
| Union Bespoke Joinery Ltd | Manufacturing | 2026 |
| Union Street VG Limited | Real estate | 2023 |
| Uniplanner Ltd | Administrative & support | 2017 |
| Unique Arts Limited | Wholesale & retail | 2010 |
| Unique Property Projects Limited | Real estate | 2018 |
| Unique Spaces Ltd | Real estate | 2017 |
| Unit Art Studios Limited | Arts & recreation | 2016 |
| Unite Digital Ltd | Administrative & support | 2021 |
| United Chiropractic Association | Other services | 2000 |
| United Data Southampton Limited | Extraterritorial | 2007 |
| United Global Trading Ltd | Wholesale & retail | 2002 |
| United Trade Construction Limited | Wholesale & retail | 2026 |
| Unity Consultants Ltd | Professional & scientific | 2026 |
| Unitylab Ltd | Professional & scientific | 2018 |
| Universal Facilities Management Ltd | Other services | 2025 |