| Sames Construction Limited | Construction | 2025 |
| Sames Group Ltd | Construction | 2019 |
| Samsung SDS Europe Limited | Transport & logistics | 2000 |
| Samsung Semiconductor Europe Limited | Manufacturing | 1997 |
| Samuel James Recruitment Ltd | Administrative & support | 2020 |
| Sanbar Illusions Ltd | Arts & recreation | 2016 |
| Sandhu Food Service Ltd | Wholesale & retail | 2025 |
| Sankhyaa Limited | Information & communication | 2000 |
| Sankofa Advisory Group Ltd | Professional & scientific | 2024 |
| Sankofa Events Limited | Professional & scientific | 2024 |
| Santley Ltd | Real estate | 2013 |
| Saoas Limited | Construction | 2026 |
| Saol Productions Limited | Administrative & support | 2024 |
| Saputo Dairy UK Ltd | Financial services | 2019 |
| Saqas Limited | Real estate | 2026 |
| Sarah Adair Limited | Other services | 2017 |
| Sarai London Ltd Ltd | Wholesale & retail | 2018 |
| Sargeant Roofing Ltd | Construction | 2023 |
| SAS Screeding Ltd | Construction | 2014 |
| SAT NET Vision Limited | Construction | 2017 |
| Sataman Consultancy Ltd | Professional & scientific | 2018 |
| Satnet Ltd | Information & communication | 2024 |
| Sauas Limited | Real estate | 2004 |
| Savant Building & Maintenance Ltd | Construction | 2019 |
| Savetreez Ltd | Agriculture & fishing | 2020 |
| Savvy Media Limited | Administrative & support | 2010 |
| Savvy Momentum Limited | Real estate | 2025 |
| Sawbo Pups Limited | Agriculture & fishing | 2021 |
| Saxas Limited | Financial services | 1991 |
| SB Brickwork Limited | Construction | 2021 |
| Sbahi UK Ltd | Wholesale & retail | 2014 |
| Scandi (UK) Limited | Wholesale & retail | 2009 |
| Scandilicious Limited | Hospitality | 2018 |
| Scanlon Freight Limited | Transport & logistics | 2018 |
| SCC Property Group Ltd | Real estate | 2021 |
| Schorn + Architects Ltd | Professional & scientific | 2025 |
| SCI Translations Limited | Administrative & support | 2003 |
| Science Rewired Ltd | Health & social care | 2024 |
| Science Solutions for Education Limited | Professional & scientific | 2013 |
| Scjes Ltd | Health & social care | 2019 |
| Scooterearz Limited | Wholesale & retail | 2011 |
| Scorpicks Ltd | Arts & recreation | 2021 |
| Scott Architects Limited | Professional & scientific | 2008 |
| Screed Solutions Ltd | Construction | 2016 |
| SDF Financial Limited | Extraterritorial | 2012 |
| SDI Global Ltd | Professional & scientific | 2019 |
| Sea Dogs Consulting Limited | Professional & scientific | 2011 |
| Seafields Estates Limited | Real estate | 2017 |
| Seaford and Weybridge Limited | Wholesale & retail | 2016 |
| Seal Group Limited | Administrative & support | 2009 |
| Searlas Limited | Real estate | 2023 |
| Seasontech Ltd. | Information & communication | 2011 |
| Seawan Global Ltd | Information & communication | 2022 |
| Secan Systems Limited | Construction | 2017 |
| Second Input Limited | Professional & scientific | 2014 |
| Second Shurgard UK Limited | Transport & logistics | 2003 |
| Secr Tech Ltd | Administrative & support | 2023 |
| Security Systems Resource International Ltd | Professional & scientific | 2005 |
| Seebeck 158 Limited | Health & social care | 2018 |
| Seedwise Business Support Limited | Administrative & support | 2026 |
| Seesgp Limited | Health & social care | 2018 |
| Seidor UK Ltd | Information & communication | 2016 |
| Selby New Property Investments Limited | Real estate | 2016 |
| Sell Property Ltd | Real estate | 2023 |
| Sells Green Ltd | Wholesale & retail | 2022 |
| Serac Limited | Information & communication | 1992 |
| Serb Ltd | Wholesale & retail | 2012 |
| Serenity Property Services Limited | Real estate | 2016 |
| Service Solution & Consulting Limited | Administrative & support | 2023 |
| Serviceline Management Surrey Ltd | Education | 2019 |
| Sessionai Ltd | Information & communication | 2026 |
| Sesta Ltd | Hospitality | 2024 |
| Seven Arches Wealth Management Limited | Financial services | 2012 |
| Seven Seas Limited | Manufacturing | 1939 |
| Sg-Retail Ltd | Professional & scientific | 2009 |
| Sgcs (Surrey) Limited | Construction | 2015 |
| Sgh&P Limited | Construction | 2025 |
| Sgmdc Limited | Professional & scientific | 2018 |
| SH Capital Advisory Limited | Professional & scientific | 2025 |
| Shadbolt Consultancy Limited | Professional & scientific | 2019 |
| Shahee Libaas Limited | Wholesale & retail | 2019 |
| Shandel Properties Limited | Real estate | 1961 |
| Shandon Associates Limited | Real estate | 2001 |
| Shapd Ltd | Extraterritorial | 2022 |
| Shark Polo Ltd | Wholesale & retail | 2026 |
| SHE Shells Designs Limited | Arts & recreation | 2015 |
| Sheardown Limited | Manufacturing | 2013 |
| Sheepdog Ltd | Financial services | 2020 |
| Sheer Consult Limited | Professional & scientific | 2009 |
| Sheer Property Limited | Extraterritorial | 2006 |
| Shepperton Fitbox Ltd | Arts & recreation | 2023 |
| Shield Plumbing Ltd | Construction | 2015 |
| Shift Media Group Ltd | Information & communication | 2025 |
| Shimmer Studio Limited | Other services | 2026 |
| Shipping Industry Confidential Reporting Limited | Information & communication | 2021 |
| Ships Code Ltd | Information & communication | 2026 |
| Shiptrack Ltd | Wholesale & retail | 2024 |
| Shootcase Limited | Information & communication | 2018 |
| Shopica Ltd | Wholesale & retail | 2024 |
| Short Fuse Electrical Services Limited | Construction | 2019 |