| Signature Plants Ltd | Wholesale & retail | 2011 |
| Signwriting Solutions Ltd | Professional & scientific | 2015 |
| SIJ Property Limited | Construction | 2020 |
| Silent Space Acoustics Ltd | Manufacturing | 2021 |
| Silica Materials and Construction Limited | Construction | 2024 |
| Silkspin Limited | Wholesale & retail | 1988 |
| Silque Beauty Limited | Other services | 2026 |
| Silver Cloud Services Ltd | Information & communication | 2018 |
| Silver Gate Defence Ltd | Administrative & support | 2024 |
| Silver SKI Holidays Limited | Administrative & support | 1985 |
| Silverberry Trading Limited | Wholesale & retail | 2008 |
| Silverdale (Sydenham) Residents Association Limited | Households | 2003 |
| Silvertongue Publishing Limited | Information & communication | 2014 |
| SIM 3 Technical Repair Services Ltd | Other services | 2018 |
| Simon LEE Coaching Limited | Education | 2014 |
| Simon Miller & Company Lettings Limited | Real estate | 2008 |
| Simon Miller & Company Limited | Real estate | 2009 |
| Simon Miller Group Limited | Financial services | 2015 |
| Simon Miller Period Homes Kent Ltd | Real estate | 2012 |
| Simon Paul Limited | Information & communication | 2005 |
| Simone Wealth Management Limited | Financial services | 2024 |
| Simons Professional Cleaning Limited | Administrative & support | 2007 |
| Simonventory Group Ltd | Wholesale & retail | 2025 |
| Simplex Assets Resources Management & Services Limited | Information & communication | 2019 |
| Simply Beau Ltd | Wholesale & retail | 2026 |
| Simply Chillin Ltd | Hospitality | 2020 |
| Simply Print Partners CD Limited | Information & communication | 2010 |
| Simply Social Media Ltd | Information & communication | 2024 |
| Simplypsl Ltd | Professional & scientific | 2018 |
| Sims Family Holdings Ltd | Financial services | 2023 |
| Simscapers Limited | Arts & recreation | 2026 |
| Simtec Power Ltd | Professional & scientific | 2023 |
| Sinetronix Ltd | Information & communication | 2017 |
| Singleton Software Limited | Information & communication | 2015 |
| Singularbit Limited | Administrative & support | 2014 |
| Sinha Holdings Limited | Professional & scientific | 2020 |
| Sinlash Limited | Other services | 2017 |
| Sinouk Limited | Hospitality | 2024 |
| Siranda Limited | Real estate | 2001 |
| Sirius Search Limited | Administrative & support | 2020 |
| SIS & Co Clothing Company Ltd | Wholesale & retail | 2025 |
| Sisterfields Clothing Company Limited | Wholesale & retail | 2019 |
| SIT UP and Listen Limited | Arts & recreation | 2007 |
| Site Ace Limited | Construction | 2019 |
| Site Form Project Management Ltd | Construction | 2024 |
| Sitewizard Ltd | Information & communication | 1997 |
| Sittingbourne Car Wash Ltd | Administrative & support | 2024 |
| Sittingbourne PCN Limited | Health & social care | 2023 |
| Sittingbourne Valet Ltd | Administrative & support | 2024 |
| Sivsy Ltd | Manufacturing | 2020 |
| SIX Pump Court Limited | Extraterritorial | 2014 |
| Sizbiz Barbers Limited | Other services | 2019 |
| SJ Sabonera Skincare Limited | Wholesale & retail | 2026 |
| SJ Services (South East) Ltd | Professional & scientific | 2013 |
| SJC Technical Services Limited | Manufacturing | 2003 |
| SJC Video Media Limited | Information & communication | 2024 |
| Sjec Consulting Limited | Financial services | 2014 |
| SJF Power Solutions Ltd | Construction | 2024 |
| SJJ Management Ltd | Wholesale & retail | 2020 |
| SJL Waste Disposal Ltd | Water & waste | 2025 |
| SJM Adviser Limited | Financial services | 2009 |
| SJM Planning and Construction Ltd | Professional & scientific | 2015 |
| Sjmcarpentry Ltd | Manufacturing | 2025 |
| Sjrn Limited | Hospitality | 2024 |
| Sjrn Properties Ltd | Real estate | 2025 |
| SJW Installations (Kent) Ltd | Construction | 2021 |
| SK Arrow Ltd | Transport & logistics | 2020 |
| SK Kent Property Ltd | Real estate | 2024 |
| SK Sporting Club Ltd | Arts & recreation | 2022 |
| SKA Property Ltd | Construction | 2022 |
| SKB UK (Holdings) Limited | Financial services | 2021 |
| Skdd Ltd | Transport & logistics | 2020 |
| Skeet Building Services Ltd | Construction | 2024 |
| Skiff Associates Ltd | Information & communication | 2019 |
| Skilfulhands Plumbing & Heating Ltd | Construction | 2025 |
| Skillora Ltd | Information & communication | 2025 |
| Skills Hive Limited | Information & communication | 2011 |
| Skilltech Recruitment Automotive Ltd | Administrative & support | 2013 |
| Skilluminair Ltd | Education | 2022 |
| Skillupballers Community Interest Company | Education | 2026 |
| Skin Deep Cosmetics Ltd | Other services | 2025 |
| Skinners Carpentry Ltd | Construction | 2024 |
| Skip Hire Comparison Ltd | Administrative & support | 2016 |
| SKJ Steel Services Ltd | Construction | 2019 |
| SKL Solutions Ltd | Professional & scientific | 2022 |
| SKM Road Freight Ltd | Transport & logistics | 2025 |
| Skogen Consulting Limited | Information & communication | 2014 |
| Skrang Ltd | Health & social care | 2012 |
| SKW Holdings Limited | Administrative & support | 2016 |
| Sky Devi Limited | Wholesale & retail | 2019 |
| Sky High Aviation (GA) Limited | Transport & logistics | 2023 |
| Sky Level Constructions Ltd | Construction | 2022 |
| Skybethel Innovations Limited | Real estate | 2026 |
| Skybing Limited | Information & communication | 2024 |
| Skybridge Transfer Limited | Transport & logistics | 2026 |
| Skyerose Limited | Wholesale & retail | 2014 |
| Skyfort Services Limited | Health & social care | 2022 |
| Skyglaze Limited | Construction | 2014 |
| Skyheights Integrated Services Limited | Construction | 2018 |
| Skylark Farming Limited | Professional & scientific | 2022 |