| Square Metre London Group Ltd | Financial services | 2025 |
| Square Metre Properties Ltd | Real estate | 2025 |
| Squle UK Ltd | Wholesale & retail | 2015 |
| SR Whitton Ltd | Hospitality | 2026 |
| SRC Grooming Ltd | Other services | 2025 |
| SRH Direct Ltd | Wholesale & retail | 2023 |
| SRI Govinda Guru Swamy Mattam Ltd | Health & social care | 2025 |
| Sriwin Ltd | Hospitality | 2026 |
| SS Infotech Limited | Information & communication | 2012 |
| SS Property Consultancy Limited | Real estate | 2021 |
| SS Soft Associates Ltd | Information & communication | 2013 |
| SSM Hospitality Limited | Hospitality | 2015 |
| SSS Capital Holdings Limited | Professional & scientific | 2023 |
| SSS Property Empire Limited | Real estate | 2021 |
| ST Augustine's Community Care Trust | Health & social care | 2019 |
| ST Catherine's School Twickenham | Education | 1992 |
| ST Consulting Private Ltd | Professional & scientific | 2025 |
| ST James Capital Management Limited | Real estate | 2018 |
| ST Margaret's Property Partnership Ltd | Real estate | 2014 |
| ST Margarets Car Valeting Services Ltd | Wholesale & retail | 2015 |
| ST Margarets Road Management Company Ltd | Households | 2009 |
| ST Mary's University, Twickenham | Education | 2006 |
| ST Mary’S Students’ Union | Education | 2017 |
| ST. MS Physiotherapy Limited | Other services | 2023 |
| Stadium Support Services Rope Access Limited | Construction | 2019 |
| Stanleys Newsagent Limited | Wholesale & retail | 2020 |
| Stanski Construction Ltd | Construction | 2014 |
| Stanski Windows Group Ltd | Construction | 2017 |
| Stanton + Co HR Limited | Professional & scientific | 2020 |
| Starfirst Limited | Information & communication | 1996 |
| Statistically Speaking (2013) Limited | Professional & scientific | 2013 |
| Status Rentals Limited | Real estate | 2015 |
| Statusplace Limited | Real estate | 2004 |
| Steadfast Dynamics Ltd. | Professional & scientific | 2019 |
| Steady Pulse Transport Limited | Transport & logistics | 2026 |
| Steady Roots Properties Ltd | Real estate | 2025 |
| Steel Accounting Services Ltd | Professional & scientific | 2018 |
| Stefano Sodaro Ltd | Professional & scientific | 2021 |
| Stein's Events Limited | Hospitality | 2013 |
| Stein's Kingston Limited | Hospitality | 2007 |
| Stein's Limited | Hospitality | 2004 |
| Stella and Sons Ltd | Hospitality | 2015 |
| Stella Nova Limited | Professional & scientific | 2025 |
| Stepco Legal Services Limited | Professional & scientific | 2023 |
| Stephen Hackett Limited | Arts & recreation | 1973 |
| Stephen Mcguckin Associates Ltd | Professional & scientific | 2022 |
| Steps on Earth Ltd | Professional & scientific | 2025 |
| Sterling Advisory Services Ltd | Professional & scientific | 2017 |
| Sterling Marketing Consultancy Ltd | Professional & scientific | 2017 |
| Sterling Properties Southern Ltd | Real estate | 2024 |
| Sterling Residences Ltd | Real estate | 2016 |
| Steve Film Facilities Ltd | Transport & logistics | 2018 |
| Stevens Rrmc Limited | Professional & scientific | 2025 |
| Sthh Restaurant Ltd | Hospitality | 2021 |
| STM Environmental Consultants Limited | Professional & scientific | 2002 |
| STM Investment Holdings Limited | Financial services | 2017 |
| Stone & Ripple Ltd | Professional & scientific | 2024 |
| Stone Heritage Ltd | Manufacturing | 2025 |
| Stone Rowe Brewer LLP | | 2009 |
| Stories Travel Ltd | Administrative & support | 2024 |
| Storm Building Limited | Construction | 2008 |
| Storm Training & Development Limited | Education | 2005 |
| Stovell Associates Ltd | Professional & scientific | 2018 |
| Stradea Ltd | Professional & scientific | 2013 |
| Stranmore Properties Limited | Real estate | 2022 |
| Strategic Business Finance AD Ltd | Professional & scientific | 2023 |
| Strategic Business Finance Ltd | Professional & scientific | 2014 |
| Strategic Informatics Limited | Administrative & support | 2014 |
| Strategic Procurement Services Limited | Administrative & support | 2004 |
| Strategic Proposals (GCA) Ltd | Professional & scientific | 2009 |
| Strawberry Hill Bookkeeping Ltd | Professional & scientific | 2025 |
| Strawberry Hill Consulting Ltd | Administrative & support | 2012 |
| Strawberry Hill Enterprises Limited | Hospitality | 1990 |
| Strawberry Hill Food & Wine Limited | Wholesale & retail | 2020 |
| Strawberry Hill Golf Club (Trading) Limited | Arts & recreation | 2015 |
| Strawberry Hill Golf Club Limited | Arts & recreation | 2009 |
| Strawberry Hill House Trading Services Limited | Arts & recreation | 2011 |
| Strawberry Hill Nominees Limited | Professional & scientific | 2020 |
| Strawberry Hill Properties Limited | Real estate | 2021 |
| Stream Lyric CIC | Education | 2025 |
| Streamlined Talent Solutions Ltd | Administrative & support | 2019 |
| Street Eats Ltd | Hospitality | 2015 |
| Streets Ahead Plumbing & Heating Limited | Construction | 2016 |
| Streets Florists Limited | Wholesale & retail | 2018 |
| Streetzapp Ltd | Information & communication | 2026 |
| Stretchlight Limited | Information & communication | 2015 |
| Strong Club Limited | Manufacturing | 2017 |
| Stuart Associates Limited | Professional & scientific | 2001 |
| Stuart Wilson Sound Limited | Information & communication | 2006 |
| Studio 17 Health Hub Ltd | Health & social care | 2023 |
| Studio Arragon Ltd | Information & communication | 2020 |
| Studio Docherty Ltd | Professional & scientific | 2017 |
| Studio Infinitii Limited | Professional & scientific | 2013 |
| Studio One Graphic Design Limited | Professional & scientific | 1988 |
| Studio Twenty Two Ltd | Information & communication | 2022 |
| Studley 2020 Ltd | Construction | 2020 |
| Suart Studio Ltd | Education | 2019 |
| Such Ventures Ltd | Other services | 2021 |
| Sudgun (UK) Limited | Wholesale & retail | 2017 |
| SUE Burton Ltd | Hospitality | 2008 |