| Swastik Indian Supermarket Limited | Wholesale & retail | 2025 |
| Sweet Chilli Ltd | Extraterritorial | 2012 |
| Sweet Halal Ltd | Wholesale & retail | 2025 |
| Sweet Home Sweets Catering Services Ltd | Manufacturing | 2020 |
| Sweet Learning Ltd | Wholesale & retail | 2024 |
| Sweetapple Lane Ltd | Professional & scientific | 2016 |
| Swemtax Limited | Financial services | 2007 |
| Swift Adventure Ltd | Arts & recreation | 2023 |
| Swiftpay Technologies Ltd | Information & communication | 2023 |
| Swim England North East Limited | Education | 2019 |
| Swingrite (UK) Limited | Wholesale & retail | 2008 |
| Swinsty Fold Management Company Limited | Real estate | 2005 |
| Swires Decorators Limited | Construction | 2002 |
| Swires Farm Services Ltd | Agriculture & fishing | 2011 |
| Swires Technical Services Ltd | Other services | 2017 |
| Swiss Hostel for Girls | Hospitality | 1956 |
| Swiss Securities Limited | Extraterritorial | 2026 |
| Swiss Watches Limited | Extraterritorial | 2011 |
| Switch IT UP Limited | Administrative & support | 2021 |
| Switch Your Car Ltd | Wholesale & retail | 2024 |
| Sykes Accountancy Services Limited | Professional & scientific | 2012 |
| Sykes House Farm Limited | Wholesale & retail | 1967 |
| Sylrian Properties Limited | Financial services | 1987 |
| Synapse Trading Limited | Manufacturing | 2024 |
| Synergize Holdings Ltd | Professional & scientific | 2013 |
| Synergize Ltd | Construction | 2004 |
| Synergy 2008 Limited | Other services | 1997 |
| Synergy Hub for Trade Limited | Wholesale & retail | 2023 |
| Syniverse Technologies (Financial Clearing) Limited | Information & communication | 1999 |
| Syniverse Technologies Limited | Information & communication | 1979 |
| Syniverse Technologies Solutions Limited | Financial services | 2003 |
| Synovate Limited | Manufacturing | 2020 |
| Synthotech Limited | Professional & scientific | 1996 |
| System of Systems Medical Ltd | Professional & scientific | 2018 |
| Systems to Sales Ltd | Professional & scientific | 2025 |
| T & J Reaveley Limited | Construction | 2007 |
| T & S Durance Ltd | Construction | 2022 |
| T D Fifteen Limited | Administrative & support | 2007 |
| T DUB Properties Limited | Real estate | 2016 |
| T Elvins Services Limited | Administrative & support | 2018 |
| T F P Construction Limited | Construction | 2011 |
| T Howie Tree Specialist Limited | Administrative & support | 2022 |
| T Vision UK Limited | Financial services | 2024 |
| T&S Issa Ltd | Other services | 2020 |
| T-Mass Ltd | Wholesale & retail | 2022 |
| T. and R. Developments Limited | Real estate | 1971 |
| T. B. Properties (Yorkshire) Limited | Construction | 2024 |
| T. G. Brokers Ltd | Wholesale & retail | 2005 |
| T.A.C. Farm Services Limited | Administrative & support | 1995 |
| T.P. Jones & Co LLP | | 2005 |
| T1 Asset Management Limited | Real estate | 2014 |
| T4NDOORI Ltd | Extraterritorial | 2017 |
| T4XI Ltd | Extraterritorial | 2019 |
| TAB Transport Ltd | Transport & logistics | 2019 |
| Tabby & Co Limited | Administrative & support | 2005 |
| Tabitha Limited | Extraterritorial | 2026 |
| Tableform Ltd | Manufacturing | 2007 |
| Taddeo Tattoo Ltd | Other services | 2024 |
| Taee Unity Investments LLP | | 2018 |
| Taikoo Books Limited | Wholesale & retail | 1978 |
| Tailwind Studio Limited | Arts & recreation | 2025 |
| TAK YAN Ltd | Hospitality | 2021 |
| Take on Talent Limited | Information & communication | 2019 |
| Talbot Jennings Limited | Extraterritorial | 2026 |
| Talen Development Consultants Limited | Construction | 2019 |
| Talent 4 Good Ltd | Administrative & support | 2025 |
| Talent Nova Ltd | Professional & scientific | 2023 |
| Talentmind Ltd | Administrative & support | 2017 |
| Talk Coatings Limited | Extraterritorial | 2021 |
| Talk GB Group Limited | Extraterritorial | 2025 |
| Talk to Neon (London) Limited | Administrative & support | 2012 |
| Talking Therapy Ltd | Professional & scientific | 2013 |
| Tall BOY (Harrogate) Ltd | Professional & scientific | 2024 |
| Tamaki Tefl Recruitment Limited | Administrative & support | 2015 |
| Tamarama Limited | Financial services | 2026 |
| Tamsynsg Ltd | Financial services | 2026 |
| Tanasuq Interactive Experience Company Ltd | Wholesale & retail | 2022 |
| Tanatus Developments Limited | Administrative & support | 2019 |
| Tanatus Holdings Limited | Administrative & support | 2019 |
| Tanfastic Ltd | Extraterritorial | 2012 |
| Tang Hall Projects Limited | Real estate | 2022 |
| Tangent Category Solutions Ltd | Professional & scientific | 2014 |
| Tangible E-Ideas Ltd | Information & communication | 2011 |
| Tanglewood Towers Limited | Real estate | 2007 |
| Tankind Limited | Other services | 2016 |
| Tapsquared Ltd | Wholesale & retail | 2026 |
| Tara Sagar Creative Ltd | Arts & recreation | 2023 |
| Tariff Limited | Extraterritorial | 2026 |
| Tarn Ventures Limited | Financial services | 2008 |
| Tarracrest Limited | Households | 1975 |
| Tarsh Williamson Ltd | Administrative & support | 2018 |
| Taste of Bengal Yorkshire Ltd | Hospitality | 2024 |
| Tasteofsouthindia Ltd | Manufacturing | 2026 |
| Tate Consulting (UK) Limited | Professional & scientific | 2013 |
| Tate Estates (Baildon) Limited | Real estate | 2018 |
| Tate Estates (Lambert House) Limited | Real estate | 2018 |
| Tate Estates Limited | Real estate | 2018 |
| Tate Group Ltd | Professional & scientific | 2022 |
| Taurity Ltd | Professional & scientific | 2024 |
| Taverna Harrogate Limited | Hospitality | 2019 |