| SNR Business Consultancy Ltd | Professional & scientific | 2020 |
| Snug Pods Europe Ltd | Administrative & support | 2023 |
| So'Dran Ltd | Wholesale & retail | 2013 |
| Sobriety Sisterhood Limited | Other services | 2021 |
| Social Chatts Limited | Information & communication | 2022 |
| Social Dynamic Solutions Limited | Health & social care | 2016 |
| Social Enterprise 18 Academy CIC | Administrative & support | 2025 |
| Social Yachting Club Limited | Administrative & support | 2019 |
| Sodhi Investments Ltd | Real estate | 2025 |
| Sofiandra UK Ltd | Health & social care | 2017 |
| Soft Landing Production Limited | Information & communication | 2016 |
| Software Insight Solutions Limited | Information & communication | 2018 |
| Solace IT Consulting Ltd | Information & communication | 2023 |
| Solad Synergy Limited | Information & communication | 2024 |
| Solar Home Solutions Limited | Real estate | 2022 |
| Solar Tackle Limited | Wholesale & retail | 2004 |
| Sole Street Track Solutions Limited | Hospitality | 2025 |
| Solid IT Consulting Ltd | Information & communication | 2016 |
| Solid Prime Homes Ltd | Real estate | 2012 |
| Solis Building Solutions Ltd | Construction | 2025 |
| Solitaire London Ltd | Wholesale & retail | 2022 |
| Solutions Critical (Events) Limited | Administrative & support | 2013 |
| Solutions Terminal Limited | Information & communication | 2011 |
| Solutions&Innovations Ltd | Information & communication | 2011 |
| Solvida Limited | Information & communication | 2010 |
| Sonbru Investments Ltd | Real estate | 2020 |
| Sonic Security Systems Ltd. | Administrative & support | 2011 |
| Sonic Wood Limited | Manufacturing | 2026 |
| Sonkay Ltd | Professional & scientific | 2023 |
| Sonnerberg Ltd | Professional & scientific | 2021 |
| Sonstone UK Ltd. | Construction | 2009 |
| Sonuvi Limited | Health & social care | 2019 |
| Sonya Wood Limited | Health & social care | 2022 |
| Sophia Slays Ltd | Real estate | 2022 |
| Sophie Williams Design Ltd | Professional & scientific | 2025 |
| Sorju Ltd | Transport & logistics | 2024 |
| Sorrel & Grey Ltd | Information & communication | 2016 |
| Sortoro and Smycke Ltd | Manufacturing | 2025 |
| Sortstay Ltd | Real estate | 2025 |
| SOS Care Consult Limited | Health & social care | 2021 |
| SOS Clothes Limited | Wholesale & retail | 2008 |
| SOS Electrical Solutions Ltd | Construction | 2026 |
| Sosec UK Ltd | Construction | 2023 |
| Soshall Consulting Limited | Administrative & support | 2012 |
| Soteric Business Corporation Limited | Information & communication | 2015 |
| SOUL46 Ltd | Hospitality | 2021 |
| Sound Metal Limited | Wholesale & retail | 2018 |
| Soundz FM Ltd | Information & communication | 2026 |
| Soundz Radio CIC | Information & communication | 2026 |
| Sourcechain Limited | Other services | 2001 |
| South Darenth Farms and Cold Store Company Limited | Agriculture & fishing | 1960 |
| South Darenth Management Company Limited | Households | 1982 |
| South Earth Ltd | Real estate | 2024 |
| South East Catering Co Ltd | Wholesale & retail | 2020 |
| South East Catering Services Ltd | Wholesale & retail | 2007 |
| South East Hire Limited | Construction | 2017 |
| South East Omnibus Ltd | Transport & logistics | 2023 |
| South East Refurbishments & Renovations Ltd | Construction | 2024 |
| South East Solar Power Limited | Other services | 2022 |
| South East Success Ltd | Professional & scientific | 2026 |
| South East Vehicle Services Ltd | Wholesale & retail | 2020 |
| South East Waste Management Ltd | Water & waste | 2024 |
| South East Windscreens Limited | Wholesale & retail | 2021 |
| South Essex Scaffolding Ltd | Construction | 2022 |
| South London Plant & Tool Hire Ltd | Administrative & support | 2025 |
| South London Timber Company Limited | Wholesale & retail | 1987 |
| South Stone Construction Ltd | Construction | 2024 |
| South Thames Taekwondo Academy Ltd | Education | 2026 |
| Southampton Way GU Limited | Construction | 2020 |
| Southampton Way Invest Ltd | Construction | 2019 |
| Southampton Way PS Limited | Construction | 2020 |
| Southbeck Investment Company Limited | Real estate | 1963 |
| Southbound London Limited | Hospitality | 2017 |
| Southern Automatic Gate Systems Limited | Construction | 2012 |
| Southern Counties Management Limited | Real estate | 2008 |
| Southern Damp Co Ltd | Construction | 2025 |
| Southern Damp Proofing Specialists Limited | Construction | 2026 |
| Southern Roofing & Building Supplies Limited | Construction | 1999 |
| Southern Soft Water Ltd | Construction | 2022 |
| Southwark Safety Limited | Professional & scientific | 2010 |
| Sovereign Design Group Ltd | Construction | 2019 |
| Sovereign Logistics Limited | Transport & logistics | 1996 |
| Sovereign Roofing & Building Ltd | Construction | 2025 |
| SOVEREIGN11425 Limited | Agriculture & fishing | 2025 |
| Soysambu Conservancy (UK) Limited | Agriculture & fishing | 2011 |
| SP Ductwork Limited | Construction | 2025 |
| SP Surveying Solutions Ltd | Professional & scientific | 2023 |
| Spa Partners Ltd | Real estate | 2019 |
| Spa Residential Home Limited | Health & social care | 2002 |
| Spa to YOU Ltd | Wholesale & retail | 2013 |
| Spaace Limited | Real estate | 2019 |
| Space Control Limited | Real estate | 2019 |
| Space Raiders Limited | Construction | 2016 |
| Space Shark Media Ltd | Information & communication | 2017 |
| Spar Services Ltd | Information & communication | 2022 |
| Spark Assets Limited | Real estate | 2022 |
| Sparkanical Ltd | Construction | 2026 |
| Sparkle Diamond International Limited | Health & social care | 2011 |
| Sparklight Support Services Ltd | Construction | 2025 |
| Sparkling ALL Solutions Ltd | Professional & scientific | 2023 |