| Silverfish & Friends Limited | Extraterritorial | 2015 |
| Silverlining Limited | Administrative & support | 2016 |
| Simon Bigrave Electrics Ltd | Construction | 2023 |
| Simon French Property Limited | Real estate | 2026 |
| Simon Hurst Consulting Ltd | Information & communication | 2021 |
| Simplepc’S Ltd | Wholesale & retail | 2025 |
| Simply Directories Ltd | Information & communication | 2012 |
| Simplycloud Solutions Ltd | Information & communication | 2021 |
| Sims Tropical Fish Limited | Wholesale & retail | 2019 |
| Simz Ltd | Real estate | 2026 |
| Sinclair & Jones Building Contractors Ltd | Construction | 2018 |
| Sindall Building Contractors Ltd | Construction | 2022 |
| Sioamon Limited | Wholesale & retail | 2025 |
| Sipl Consulting Services Ltd | Administrative & support | 2014 |
| Sitech Trading Ltd | Wholesale & retail | 2025 |
| SIX H Consulting Limited | Administrative & support | 2020 |
| SJ Property Sourcing Ltd | Real estate | 2024 |
| SJ Stayaways Ltd | Real estate | 2025 |
| SJA Media Services Limited | Information & communication | 2011 |
| SJB Legal Services Limited | Professional & scientific | 2015 |
| Sjfb Limited | Information & communication | 2011 |
| Skatebiscuits Ltd | Other services | 2009 |
| Skiathos Travel Limited | Administrative & support | 2000 |
| Skilam Limited | Arts & recreation | 2024 |
| Skill and Story CIC | Administrative & support | 2025 |
| Skin Utopia Limited | Health & social care | 2020 |
| Skunkworks Racing Ltd | Arts & recreation | 2024 |
| Sky Line Delivery Ltd | Transport & logistics | 2025 |
| Skybridge Security Limited | Administrative & support | 2010 |
| Skyhawk Exterior Cleaning Ltd | Construction | 2024 |
| Skyline H Y Construction Ltd | Construction | 2024 |
| Slap That Sound Ltd | Arts & recreation | 2022 |
| Slaugham Community CIC | Construction | 2022 |
| Slaugham Place Events Limited | Arts & recreation | 2018 |
| SLB and SON Scaffolding Limited | Construction | 2022 |
| Sleeping Lions Limited | Manufacturing | 2002 |
| Slideficient UK Ltd | Professional & scientific | 2025 |
| SM Roofing Maintenance Ltd | Construction | 2025 |
| Small Nails Limited | Professional & scientific | 2004 |
| Smallfield Garage Limited | Wholesale & retail | 2016 |
| Smalltalk Systems Limited | Extraterritorial | 1998 |
| Smart Choice Repairs Ltd | Wholesale & retail | 2026 |
| SMB Sales & Designs Limited | Wholesale & retail | 2015 |
| Smith's Interiors Limited | Manufacturing | 2016 |
| SMS Advisory Limited | Professional & scientific | 2022 |
| Snack Fetch and Bark Limited | Wholesale & retail | 2025 |
| SNC Construction Limited | Construction | 2021 |
| Snoose Limited | Administrative & support | 2023 |
| Snorr Properties Ltd | Hospitality | 2021 |
| Snowdrop Marketing Ltd | Administrative & support | 2019 |
| SNOWDROPRH16 Ltd | Hospitality | 2023 |
| SOB Promotions Limited | Administrative & support | 2024 |
| Sobesa Technology Limited | Information & communication | 2015 |
| Soccer Stateside Limited | Arts & recreation | 2017 |
| Social Research Associates Limited | Professional & scientific | 2021 |
| Socius Network Limited | Administrative & support | 2008 |
| Soft Skills at Work Limited | Professional & scientific | 2013 |
| Softsource Investments Limited | Real estate | 2009 |
| Solaris Tech Limited | Information & communication | 2005 |
| Solarvictus Limited | Other services | 2012 |
| Solaz Health Ltd | Health & social care | 2025 |
| Sole Kids Ltd | Wholesale & retail | 2021 |
| Solergy Ltd | Construction | 2024 |
| Solid Fluid (System Solutions) Limited | Manufacturing | 2009 |
| Solkemist Limited | Health & social care | 2023 |
| Solutions Alliance Limited | Information & communication | 2017 |
| Solutions in I.T. Limited | Information & communication | 2002 |
| Solvolution Accounts Ltd | Professional & scientific | 2014 |
| Solvolution Limited | Professional & scientific | 2001 |
| Somnio Productions Ltd | Information & communication | 2014 |
| Sonab (UK) Limited | Real estate | 2016 |
| Sonile Ltd | Health & social care | 2018 |
| Sophie Ingeborg Hatcher Limited | Professional & scientific | 2024 |
| Sophie J Skinner Limited | Administrative & support | 2012 |
| Sophie Joanna Events Limited | Administrative & support | 2023 |
| Sophie Stanbury Interiors Limited | Wholesale & retail | 2014 |
| Soto Clothing Limited | Wholesale & retail | 2024 |
| Sought Property Ltd | Professional & scientific | 2023 |
| Soul Speaker Ltd | Education | 2024 |
| Soulmates Academy Limited | Education | 2017 |
| Sound Matters Ltd | Education | 2019 |
| South Coast Damp Proofing Ltd | Manufacturing | 2018 |
| South Downs Kitchens Limited | Construction | 2025 |
| South East Business Systems Limited | Information & communication | 1980 |
| South East Planning Consultancy Ltd | Professional & scientific | 2022 |
| South East Roofing Services Limited | Construction | 2011 |
| South East Roofing Supplies Ltd | Wholesale & retail | 2018 |
| South East Sash Window Experts Ltd | Construction | 2019 |
| South East Tankers Ltd | Water & waste | 2023 |
| South of England Agricultural Society(The) | Other services | 1954 |
| South of England Event Centre Limited | Other services | 1988 |
| South Road Estates Ltd | Real estate | 2025 |
| South Saxon Ltd | Professional & scientific | 2025 |
| South West London Surveyors Limited | Professional & scientific | 2013 |
| Southdown Interiors Limited | Other services | 2009 |
| Southern Construction Consulting Limited | Professional & scientific | 2019 |
| Southgate Consulting Services Ltd | Professional & scientific | 2019 |
| Southwood Project Management Ltd | Professional & scientific | 2024 |
| Sovereign Business Jets Limited | Transport & logistics | 2003 |
| Sovereign Completions Limited | Manufacturing | 2024 |