| Sweet-Creation Limited | Hospitality | 2012 |
| Sweets to the Beat Limited | Wholesale & retail | 2013 |
| Swift Holdings Southern Limited | Financial services | 2024 |
| Swift PAY Group Ltd | Professional & scientific | 2020 |
| Swift Recruitment Limited | Administrative & support | 2017 |
| Swift Recycling Limited | Water & waste | 2018 |
| Swift Sales Recruitment Limited | Administrative & support | 2025 |
| Swiftglobal Commerce Limited | Wholesale & retail | 2025 |
| Swimstar Analytics Ltd | Information & communication | 2023 |
| Swiss Painters & Decorators Limited | Construction | 2023 |
| Swordfish Homes Limited | Construction | 2022 |
| Swpm Limited | Real estate | 2000 |
| Swyn Engineering Consultants Ltd | Professional & scientific | 2025 |
| Sycamore Car Sales Limited | Wholesale & retail | 2013 |
| SYD Lawrence Orchestra Limited | Administrative & support | 2008 |
| Sydney Smith Marketing Limited | Professional & scientific | 2026 |
| Sydneyval Holdco Ltd | Information & communication | 2025 |
| Sylvadale Limited | Construction | 2012 |
| Sylvan Glade Ltd | Hospitality | 2014 |
| Sync Design Limited | Administrative & support | 2012 |
| Syndio Solutions Limited | Administrative & support | 2022 |
| Synergie Systems Ltd | Administrative & support | 2021 |
| Synergy Business Partnerships Ltd | Professional & scientific | 2020 |
| Synergy Landmarks Ltd | Real estate | 2025 |
| Synergy Success Network Ltd | Education | 2018 |
| Synergy Wealth Creation Ltd | Real estate | 2020 |
| System Genome Ltd | Professional & scientific | 2026 |
| Systms Ltd | Information & communication | 2025 |
| SZ Dance Academy Ltd | Education | 2024 |
| Szroktek Ltd | Manufacturing | 2024 |
| Szwarc.Polishing Ltd | Manufacturing | 2018 |
| T & F Enterprise Ltd | Wholesale & retail | 2023 |
| T & G Brickwork Limited | Wholesale & retail | 2005 |
| T & J Decorators Limited | Construction | 2014 |
| T & NG Group Ltd | Health & social care | 2020 |
| T & V Limited | Real estate | 1934 |
| T and B Nurserys Ltd | Wholesale & retail | 2023 |
| T Coleborn and SON Limited | Construction | 1998 |
| T G Williams Electrical Ltd | Construction | 2020 |
| T H Hicks Limited | Professional & scientific | 2014 |
| T J Davis & SON Ltd | Arts & recreation | 2026 |
| T J Medical Services Ltd | Administrative & support | 2014 |
| T Jones Group Limited | Financial services | 2017 |
| T Nail Spa Ltd | Other services | 2025 |
| T Roberts Consulting Ltd | Manufacturing | 2021 |
| T S E Carpentry & Construction Limited | Construction | 2022 |
| T Todoroff Ltd | Financial services | 2017 |
| T W (Portsmouth) Limited | Households | 2022 |
| T&A Property Rentals Ltd | Real estate | 2025 |
| T&J Facades Ltd | Construction | 2018 |
| T&P Homes Limited | Real estate | 2019 |
| T&S Rooms Ltd | Real estate | 2015 |
| T-Adams Concept Limited | Professional & scientific | 2025 |
| T.Couzens & Sons Limited | Construction | 1931 |
| T.E.H. Management and Holdings Ltd | Professional & scientific | 2017 |
| T.I.P.C.I Group Limited | Administrative & support | 2016 |
| T.S. Recovery Limited | Other services | 2009 |
| T1 Legal Limited | Professional & scientific | 2018 |
| T2 Merchant Solutions Ltd | Administrative & support | 2019 |
| Tabarin Logistics Ltd | Administrative & support | 2013 |
| Tables Leasehold Ltd | Real estate | 2025 |
| Tadas DRY Lining Limited | Construction | 2008 |
| Tadgt Digital Solutions Limited | Information & communication | 2025 |
| Tadgt Payment Solutions Limited | Financial services | 2025 |
| TAG Trading Limited | Wholesale & retail | 2024 |
| Taganz Medical Limited | Health & social care | 2026 |
| Tahikostitch Ltd | Manufacturing | 2023 |
| Tahir's Property Empire Ltd | Real estate | 2012 |
| Tahmina Ltd | Hospitality | 2020 |
| Tahsin Group Limited | Information & communication | 2025 |
| Tailored Linguistic Services Limited | Professional & scientific | 2025 |
| Tailored Painting & Decorating Limited | Construction | 2005 |
| Tails-A-Waggin Limited | Agriculture & fishing | 2016 |
| Takedown Festival Limited | Arts & recreation | 2022 |
| Taking Shape Design Ltd | Professional & scientific | 2026 |
| Takumi Holdings Ltd | Real estate | 2025 |
| Talent Groupuk Limited | Administrative & support | 2025 |
| Taliah Spice Ltd | Hospitality | 2025 |
| Talib Consultancy (UK) Limited | Other services | 2011 |
| Talisman Building Ltd | Construction | 2025 |
| Talnet Ltd | Real estate | 2026 |
| Talos Automation Limited | Extraterritorial | 2002 |
| Tamgostair Holdings Limited | Professional & scientific | 2015 |
| Tammz Limited | Real estate | 2009 |
| Tan-Xs Limited | Other services | 2003 |
| Tanaholic Ltd | Other services | 2025 |
| Tang's Enterprises (U.K.) Limited | Real estate | 1996 |
| Tangier Road Butchers Ltd | Other services | 2010 |
| Taplow Electrics Ltd | Construction | 2023 |
| Taps Dream Limited | Real estate | 2025 |
| Target Interior Solutions Limited | Construction | 2021 |
| Target Interior Solutions. Southern Limited | Construction | 2024 |
| Targeted SEO Limited | Information & communication | 2017 |
| Targett Carpentry Ltd | Construction | 2025 |
| Targett Homes Limited | Real estate | 2026 |
| Tarring Community Pharmacy Ltd | Wholesale & retail | 2009 |
| Tashe Ltd | Health & social care | 2022 |
| Tashmav Limited | Administrative & support | 2019 |
| Taste of India (Portsmouth) Ltd | Hospitality | 2019 |
| Tastepod Ltd | Wholesale & retail | 2026 |