| Swindon Motorsports Ltd | Real estate | 2022 |
| Swipewire Enterprise Limited | Wholesale & retail | 2022 |
| Swire Ltd | Professional & scientific | 2026 |
| Swiss Centre UK (Centrum Helveticum Britanniae) Ltd | Other services | 2026 |
| Swiss Link Straps Ltd | Manufacturing | 2024 |
| Switch Electrical Group Limited | Construction | 2021 |
| SWL Security Services Limited | Administrative & support | 2009 |
| SWP Sitings Limited | Construction | 2017 |
| Sxndybrown Films Ltd | Information & communication | 2023 |
| Syar Ltd | Financial services | 2024 |
| Sydtraffik Ltd | Construction | 2018 |
| Syed Empire Ltd | Wholesale & retail | 2024 |
| Sykes Property Investment Group Limited | Real estate | 2016 |
| Sylvaner Limited | Real estate | 2010 |
| Symes Mansion Limited | Households | 1992 |
| Symsmart Ltd | Professional & scientific | 2016 |
| Synapsesoft Ltd | Information & communication | 2025 |
| Synaptics Energy Solutions Limited | Construction | 2016 |
| Synaptics EVS Limited | Construction | 2022 |
| Synaptics Specialist Fabrications Limited | Professional & scientific | 2025 |
| Synchgo Limited | Wholesale & retail | 2019 |
| Synchronised Software Limited | Professional & scientific | 2020 |
| Synclipse Ltd | Information & communication | 2025 |
| Synigemedx Ltd | Health & social care | 2024 |
| Synpro Media UK Ltd | Information & communication | 2025 |
| Syntaxion Limited | Information & communication | 2020 |
| Syntia Ltd | Information & communication | 2025 |
| Syntyl Ltd | Information & communication | 2012 |
| Syrus Group Ltd | Administrative & support | 2016 |
| System 26 Ltd | Professional & scientific | 2026 |
| System Development INT Limited | Information & communication | 2011 |
| System Work BR Ltd | Information & communication | 2025 |
| Systems & Applied Intelligence Limited | Information & communication | 2018 |
| SZB Advisors Ltd | Professional & scientific | 2016 |
| T a Colbourne Projects Ltd | Construction | 2013 |
| T a Saunders Investments LLP | | 2006 |
| T and D Luxury Properties Ltd | Real estate | 2024 |
| T Fit Holdings Limited | Real estate | 2024 |
| T Fit Icen Way Limited | Real estate | 2024 |
| T H Landscaping & Design Ltd | Administrative & support | 2013 |
| T Harriman Consulting Ltd | Information & communication | 2023 |
| T Hill Decorating Services Ltd | Construction | 2023 |
| T J Graham Limited | Hospitality | 2005 |
| T P Plumbing Services (Dorset) Ltd | Construction | 2013 |
| T P Sherwood & Sons Ltd | Administrative & support | 2021 |
| T R B Brickwork Contractors Ltd | Construction | 2017 |
| T&A Business Consulting Ltd | Professional & scientific | 2026 |
| T&A Consult Ltd | Real estate | 2025 |
| T&A Housing (UK) Ltd | Real estate | 2019 |
| T&A Housing UK-1 Ltd | Real estate | 2023 |
| T&G-Promech Limited | Manufacturing | 2015 |
| T&H Homewares Ltd | Wholesale & retail | 2023 |
| T&T Automotive Limited | Manufacturing | 2014 |
| T-Fund GP Limited | Extraterritorial | 2008 |
| T. Cattell Contracting Services Limited | Construction | 2019 |
| T. Henry Limited | Professional & scientific | 2018 |
| T.A.N.I. Collective Limited | Professional & scientific | 2025 |
| T.C. Lowes Building & Paving Limited | Construction | 2023 |
| T.G. Smyth Limited | Hospitality | 1986 |
| T.W. Clayton (Poole) Limited | Manufacturing | 1989 |
| T3 Property Developments Ltd | Construction | 2025 |
| T4 Digital Futures Ltd | Information & communication | 2021 |
| Tablish Ltd | Information & communication | 2011 |
| Tabram Limited | Construction | 2024 |
| Tabulara Limited | Information & communication | 2020 |
| Tacladders IT Solutions PVT Ltd | Information & communication | 2024 |
| Tadmarton Products Limited | Transport & logistics | 1971 |
| TAEKWONDO4LIFE Limited | Arts & recreation | 2015 |
| TAG and Tails Ltd | Information & communication | 2024 |
| TAG Carpentry and Building Ltd | Construction | 2022 |
| TAG Media Group and Holding Limited | Wholesale & retail | 2025 |
| TAG Technology Systems Ltd | Manufacturing | 2024 |
| Tagus TV Limited | Information & communication | 2019 |
| Tahira Perveen Ltd | Wholesale & retail | 2025 |
| Taiga Group Limited | Wholesale & retail | 2024 |
| Tailaura Ltd | Wholesale & retail | 2025 |
| Tailor Paved Ltd | Administrative & support | 2020 |
| Tailor Windows Ltd | Construction | 2019 |
| Tailored Apartments Ltd | Real estate | 2020 |
| Tailored Mark Ltd | Real estate | 2024 |
| Tailored Plastering Ltd | Construction | 2023 |
| Tailored Tastes Catering Ltd | Hospitality | 2023 |
| Tailored View Home Improvements Limited | Construction | 2016 |
| Taisteal Ltd | Professional & scientific | 2023 |
| Takanoha Limited | Information & communication | 2019 |
| Take a BAO Trading Ltd | Hospitality | 2026 |
| Take One Location Security Limited | Administrative & support | 2025 |
| Take Profit Crypto CEW Limited | Professional & scientific | 2022 |
| Take Your Protection Ltd | Information & communication | 2018 |
| Take Your Time Limited | Wholesale & retail | 2020 |
| Taktika Business Solutions Limited | Professional & scientific | 2005 |
| Talbot Park Nursery Ltd | Education | 2002 |
| Talent Drive Ltd | Administrative & support | 2019 |
| Talent Finance Ltd | Administrative & support | 2023 |
| Talent Group Holdings Ltd | Financial services | 2023 |
| Talessa Limited | Real estate | 1946 |
| Talis Surveying Limited | Professional & scientific | 2016 |
| Talisman Property Investments Limited | Real estate | 2014 |
| Talking Heads Bournemouth Ltd | Other services | 2011 |
| Tallawah Outpost Ltd | Administrative & support | 2025 |