| Sundvik Homes Ltd | Construction | 2020 |
| Sunninghill Court Residents Association Limited | Households | 1989 |
| Sunnyside Systems Limited | Information & communication | 2025 |
| Sunset Sugar Studios Limited | Information & communication | 2022 |
| Sunshine Consultancy London Limited | Professional & scientific | 2013 |
| Sunshine Medical Professionals Limited | Health & social care | 2014 |
| Supa Sports Limited | Wholesale & retail | 1980 |
| Supamix Limited | Professional & scientific | 1960 |
| Supanova Radiation Protection Services Limited | Professional & scientific | 2025 |
| Super Spark Services Ltd | Construction | 2021 |
| Super Sports Limited | Wholesale & retail | 1980 |
| Superdata Technologies Ltd | Information & communication | 2015 |
| Superfied Ltd | Wholesale & retail | 2018 |
| Supply Kernel Ltd | Wholesale & retail | 2022 |
| Supporta International Limited | Professional & scientific | 2019 |
| Surefoot Communications Ltd | Professional & scientific | 2001 |
| Surgease Innovations Limited | Professional & scientific | 2016 |
| Surgra Ltd | Financial services | 2023 |
| Surico Limited | Professional & scientific | 2010 |
| Surrey and Sussex Breast Surgeon Ltd | Health & social care | 2025 |
| Surrey Urological Ltd | Health & social care | 2011 |
| Survey & Engineering Services Limited | Professional & scientific | 2005 |
| Survey MAX Limited | Wholesale & retail | 2013 |
| Survey Network MPC Limited | Professional & scientific | 2024 |
| Suseco Limited | Professional & scientific | 2019 |
| Sushi Point Maidenhead Ltd | Wholesale & retail | 2023 |
| Susie March Consulting Ltd | Education | 2022 |
| Sustainable Marketing Compass Ltd | Professional & scientific | 2023 |
| Sustineri Strategy Ltd | Professional & scientific | 2022 |
| Suvarna Technologies Limited | Information & communication | 2015 |
| Suzanne Laird Consultancy Services LLP | | 2023 |
| SVG Motorsport Ltd | Wholesale & retail | 2024 |
| SVL1 Limited | Real estate | 2021 |
| SVL2 Ltd | Real estate | 2022 |
| SVL3 Limited | Real estate | 2022 |
| SW Stage School LLP | | 2025 |
| Swanuppers Ltd | Hospitality | 2022 |
| Swap Heating Ltd | Construction | 2023 |
| Swaryarth AI Solutions Limited | Information & communication | 2024 |
| Swearingdad Design Ltd | Professional & scientific | 2016 |
| Swift Estimating Services Limited | Professional & scientific | 2010 |
| Swift Flow Contractor Ltd | Construction | 2023 |
| Swift Outlet Ltd | Wholesale & retail | 2020 |
| Swiftrapid Limited | Professional & scientific | 1995 |
| Swiftridge Logistics Ltd | Transport & logistics | 2025 |
| Swishing Limited | Wholesale & retail | 2010 |
| Swoppsy Ltd | Manufacturing | 2022 |
| Sword Services Limited | Construction | 2004 |
| Sworm Ltd | Wholesale & retail | 2025 |
| Sxsubsea Limited | Mining & quarrying | 2004 |
| Sybr Studio Limited | Professional & scientific | 2025 |
| Sycamore (UK) Limited | Manufacturing | 1997 |
| Sylvan Investment Limited | Construction | 2023 |
| Synamedia Holdings Limited | Financial services | 2018 |
| Synamedia Limited | Information & communication | 1995 |
| Synergic Solutions Limited | Professional & scientific | 2024 |
| SYS I Limited | Information & communication | 2017 |
| Systec Limited | Information & communication | 2008 |
| T & Crew LLP | | 2007 |
| T & H (Essex) Limited | Other services | 2015 |
| T & R Properties (H-W) Limited | Real estate | 2011 |
| T & R Transport Limited | | 1982 |
| T Knowles Carpentry Limited | Construction | 2025 |
| T&K Foreign Trade Limited | Wholesale & retail | 2021 |
| T. Jones & SON (Builders & Decorators) Limited | Administrative & support | 1997 |
| T.S. Property Maintenance Contractors Limited | Construction | 2006 |
| T.S.Ground and Sons Limited | Construction | 1972 |
| T.W. Hamilton Design Limited | Manufacturing | 1979 |
| TA Angles Ltd | Health & social care | 2015 |
| TAB Solutions Limited | Construction | 2014 |
| Tacet 5 Limited | Professional & scientific | 2017 |
| Tackletek Limited | Education | 2024 |
| Tacman Interiors Ltd | Construction | 2024 |
| Tadley Healthcare Limited | Health & social care | 2000 |
| Tail END Caterers Limited | Hospitality | 2008 |
| Tailored Primary Care Ltd | Administrative & support | 2024 |
| TAK TIK Ltd | Professional & scientific | 2014 |
| Take Two Travel Solutions Limited | Other services | 2020 |
| TAKE2ETON Luxury & Private Travel Solutions Limited | Administrative & support | 2024 |
| Taketwo Eton Group Limited | Other services | 2021 |
| Takwin UK Ltd | Real estate | 2024 |
| Tala Logistics Ltd | Transport & logistics | 2011 |
| Tales on Tables Ltd | Manufacturing | 2025 |
| Talk Plan Build Ltd | Professional & scientific | 2024 |
| Talking Mental Health Ltd | Information & communication | 2020 |
| Talland Consulting Limited | Agriculture & fishing | 2019 |
| Tamana Superstore Ltd | Wholesale & retail | 2017 |
| Tamasha Food Ltd | Real estate | 2014 |
| Tamatijack Limited | Real estate | 2019 |
| Tani Properties Limited | Real estate | 2025 |
| Tano Global Food Safety Limited | Hospitality | 2025 |
| Tantropaya Consulting Limited | Information & communication | 2010 |
| Tapestry Management Limited | Professional & scientific | 2007 |
| Taplow & Hitcham Recreation Grounds Association Limited(The) | Arts & recreation | 1956 |
| Taplow Lake CIC | Real estate | 2015 |
| Taplow Lakeside OWS Ltd | Arts & recreation | 2024 |
| Taplow Motor Company Limited | Wholesale & retail | 2026 |
| Tarcus Properties Limited | Construction | 1976 |
| Target Pathways Ltd | Information & communication | 2026 |
| Task Corporate Solutions Limited | Professional & scientific | 2007 |