| Smiley Cleaning Services Ltd | Administrative & support | 2025 |
| Smith & Green Security Systems Ltd | Administrative & support | 2019 |
| Smith's Consultancy Limited | Professional & scientific | 2014 |
| Smoke Bandits Ltd | Wholesale & retail | 2017 |
| Smoking Chili Media Limited | Other services | 2015 |
| SMR Commercial Services Limited | Professional & scientific | 2016 |
| SMS Electric Ltd | Construction | 2017 |
| SNA Daily Goods Ltd | Wholesale & retail | 2026 |
| Snap Floors Limited | Construction | 2025 |
| Snodie Limited | Administrative & support | 2019 |
| SO Clean HCW Ltd | Other services | 2014 |
| Soar Fitness Limited | Arts & recreation | 2026 |
| Soaring Eagles Initiative CIC | Health & social care | 2024 |
| Sochin Electronic Systems Limited | Construction | 2016 |
| Social Idol Limited | Professional & scientific | 2021 |
| Social Impact Group Limited | Professional & scientific | 2007 |
| Social Operating Systems Limited | Information & communication | 2025 |
| Sofia House Limited | Households | 2011 |
| Soif Limited | Professional & scientific | 2016 |
| SOL Attendance Limited | Education | 2013 |
| Solid Rock Studios Ltd | Real estate | 2026 |
| Solium Concepts Ltd | Wholesale & retail | 2023 |
| Soluna London Ltd | Other services | 2024 |
| Solution Management Services Limited | Professional & scientific | 2016 |
| Solutions Print Supplies Limited | Manufacturing | 2006 |
| Solvtek Limited | Information & communication | 2026 |
| Somerley Property Ltd | Real estate | 2024 |
| Sonabhi Ltd | Hospitality | 2024 |
| SONABHI1 Ltd | Professional & scientific | 2026 |
| Sondel Sport Motorcycles Ltd. | Wholesale & retail | 2018 |
| Sonic Element Limited | Professional & scientific | 2007 |
| Soold Property Enterprises Ltd | Real estate | 2025 |
| Soold Property Solutions Ltd | Real estate | 2021 |
| Sophia Electrical Limited | Construction | 2024 |
| Sophie Booth Limited | Information & communication | 2024 |
| Sophie Brooks Ltd | Other services | 2018 |
| Sophie Carter Event Production Ltd | Administrative & support | 2021 |
| Sophie Piper Ltd | Administrative & support | 2020 |
| Sophie Willard Event Management Ltd | Administrative & support | 2021 |
| Sorbis Limited | Real estate | 2004 |
| Soshall Limited | Administrative & support | 2016 |
| Sothis - the Goddess Within Limited | Arts & recreation | 2025 |
| Sotibar Limited | Wholesale & retail | 2026 |
| Soultails Limited | Transport & logistics | 2016 |
| Sounds by Ronan Ltd | Information & communication | 2023 |
| South Brixton Estates Limited | Construction | 1993 |
| South Crete Limited | Administrative & support | 2023 |
| South East Floor Coverings Ltd | Construction | 2015 |
| South East London Chamber of Commerce | Administrative & support | 2004 |
| South East London Roofing & Building Services Ltd | Construction | 2026 |
| South England Pastries Limited | Hospitality | 2014 |
| South Surfacing Limited | Construction | 2025 |
| Southeaststyleinteriors Limited | Professional & scientific | 2025 |
| Southern Control Holdings Limited | Construction | 2013 |
| Southern Control Services Limited | Construction | 1982 |
| Southern Cross Ventures Limited | Professional & scientific | 2024 |
| Southern Party Wall Surveyors Limited | Professional & scientific | 2019 |
| Southmills Trading Limited | Other services | 2009 |
| Southside Films Ltd | Information & communication | 2019 |
| Southside Partners LLP | | 2018 |
| Southwood Residential Developments Ltd | Construction | 2017 |
| Sovereign U.K. Conservatories Ltd. | | 1991 |
| SP Plumbing and GAS Limited | Construction | 2015 |
| Span-Fab Ltd | Manufacturing | 2012 |
| Sparks and Flush Ltd | Energy | 2015 |
| Spear Construction & Carpentry Ltd | Manufacturing | 2018 |
| Specialist Metal Roofing Limited | Administrative & support | 2021 |
| Specifek Ltd | Wholesale & retail | 2020 |
| Spectronet Holdings Ltd | Real estate | 2023 |
| Spectronet Limited | Information & communication | 2017 |
| Spectrum Electrical & Building Services Limited | Construction | 2021 |
| Spellbound Events Management Limited | Administrative & support | 2026 |
| Spicy Grill London Ltd | Hospitality | 2020 |
| Spin Doctor (UK) Ltd | Administrative & support | 2008 |
| Spinks Roofing Ltd | Construction | 2024 |
| Spiralfact Property Investments Limited | Real estate | 1987 |
| Spirit Commercial Limited | Extraterritorial | 2010 |
| Spirit Design Limited | Administrative & support | 2001 |
| Spirit Home Limited | Administrative & support | 2010 |
| Spirit Property and Facilities Management Limited | Other services | 2014 |
| Spit and Sawdust PUB Company Ltd | Hospitality | 2011 |
| Splinter Pink Limited | Real estate | 2010 |
| Splus Entertainment Limited | Hospitality | 2025 |
| Sport Academies Limited | Arts & recreation | 2015 |
| Sports Promotions (UK) Ltd | Administrative & support | 2011 |
| Spring Gardens Souvenir Ltd | Wholesale & retail | 2022 |
| Square Box Technical Limited | Administrative & support | 2017 |
| Square Side Limited | Construction | 2022 |
| Squared Structural Engineers Ltd | Professional & scientific | 2026 |
| Squerryes Oast Otham Ltd | Administrative & support | 2018 |
| SR Sales Limited | Administrative & support | 2024 |
| SR Sparkles Ltd | Other services | 2024 |
| SRC Installations Caterham Limited | Construction | 2019 |
| SRI P-Way Engineering Limited | Construction | 2015 |
| SRJ Plastering Ltd | Construction | 2022 |
| Srkn Ltd | Real estate | 2026 |
| Srpa Services Limited | Administrative & support | 2014 |
| SS IT Infra Ltd | Information & communication | 2024 |
| SS IT Systems Ltd | Information & communication | 2023 |
| SSC Trading Limited | Hospitality | 2016 |