| Saturn Leisure Limited | Arts & recreation | 1999 |
| Saturn QA Testing Ltd | Information & communication | 2025 |
| Savill Transport Limited | Transport & logistics | 2000 |
| SB Hair & Beauty Academy Limited | Education | 2012 |
| Scarlet Selection Ltd | Administrative & support | 2021 |
| School of Panto Ltd | Arts & recreation | 2022 |
| Scionn Business Consultancy Ltd | Information & communication | 2021 |
| SD Roofing & Building Ltd | Construction | 2025 |
| SDC Electrical Installations Ltd | Construction | 2009 |
| SDH International Ltd | Wholesale & retail | 2025 |
| Sea Hawk Maritime Limited | Administrative & support | 2011 |
| Seal Social Ltd | Professional & scientific | 2025 |
| Searle Management Consulting Ltd | Professional & scientific | 2015 |
| Seaside Brooks Holiday Apartments Ltd | Hospitality | 2021 |
| Second Coat Services Ltd | Construction | 2024 |
| Secure Property Services Ltd | Construction | 2026 |
| Seek Strategy Limited | Professional & scientific | 2019 |
| Segelu Ventures Limited | Administrative & support | 2015 |
| Self Made Speaking ACA Ltd | Financial services | 2025 |
| Selimaj Construction Ltd | Construction | 2022 |
| Sella Law Ltd | Professional & scientific | 2013 |
| Sella Solicitors LLP | | 2013 |
| Sentinel Lightning Protection & Earthing Limited | Manufacturing | 1991 |
| Sentsurvey Limited | Real estate | 1993 |
| Serious Stuff Limited | Wholesale & retail | 2009 |
| Servecom Limited | Construction | 2015 |
| Servus Properties Group Ltd | Real estate | 2020 |
| Sethi Property's Limited | Real estate | 2022 |
| Seuk Exports Limited | Wholesale & retail | 2025 |
| SGS Electrical and Cabling Ltd | Wholesale & retail | 2002 |
| SGS Holdings Kent Limited | Construction | 2025 |
| Sharp Scratch Limited | Health & social care | 2010 |
| Shear Communication (South East) Limited | Professional & scientific | 2016 |
| Shearwater Projects Limited | Real estate | 1999 |
| Shelterstone Petroleum Limited | Mining & quarrying | 2017 |
| Sherwin Publications Limited | Administrative & support | 1995 |
| Sherwoodroofing&Construction Limited | Construction | 2025 |
| Shine Hairdressing Limited | Other services | 2002 |
| Shoogi Limited | Real estate | 2023 |
| Shopaholike UK Ltd | Wholesale & retail | 2017 |
| Short Ground Limited | Health & social care | 2009 |
| Shoulderdoctor Ltd | Health & social care | 2010 |
| Showlove Productions Limited | Construction | 2025 |
| Showtime Stage Schools Limited | Professional & scientific | 2018 |
| Siglo Aviation Ltd | Financial services | 2005 |
| SIL-3 Limited | Professional & scientific | 2009 |
| Silicone Sally Ltd | Wholesale & retail | 2011 |
| Silverprior Properties Limited | Real estate | 1972 |
| Simon Paul Shutters & Blinds Limited | Construction | 2015 |
| Simplespex Limited | Health & social care | 2012 |
| Sinclair-Strong Consultants Ltd | Health & social care | 2011 |
| Sinclair-Strong Holdings Ltd | Financial services | 2022 |
| Sinclair-Strong Investments Ltd | Financial services | 2023 |
| Sinha Surgical Services Ltd | Health & social care | 2018 |
| Siteguard Ltd | Administrative & support | 2023 |
| SJ Houghton's Ltd | Wholesale & retail | 2022 |
| SJB IT Consultants Limited | Information & communication | 2016 |
| Sjjc Ltd | Financial services | 2017 |
| SJT Laumet Limited | Real estate | 2009 |
| SJV Ltd | Real estate | 2021 |
| SJW Transport Services Ltd | Manufacturing | 2025 |
| SK Companies Limited | Financial services | 2020 |
| SK LAB Limited | Wholesale & retail | 2018 |
| SK Mobile Car Wash Limited | Administrative & support | 2025 |
| SK Renovations Ltd | Construction | 2015 |
| SKA Electrical Ltd | Construction | 2018 |
| Skar Rentals Limited | Real estate | 2025 |
| Skill Birds Ltd | Administrative & support | 2020 |
| Skills to Build Ltd. | Education | 2015 |
| Skinfinity Kent Ltd | Education | 2025 |
| Skipmix U.K. Ltd. | Administrative & support | 1984 |
| Skobar Food Courier Kent Limited | Transport & logistics | 2025 |
| Skobar Investments Limited | Hospitality | 2020 |
| Skunkworks Digital Limited | Information & communication | 2019 |
| Skyhardt Ltd | Arts & recreation | 2019 |
| SLC Hire Services Ltd | Administrative & support | 2025 |
| Slender Winter Partnership Limited | Professional & scientific | 1999 |
| SLF Capital Management Ltd | Professional & scientific | 2023 |
| SLS Management Consulting Ltd | Professional & scientific | 2017 |
| SMB Records Management Ltd | Arts & recreation | 2013 |
| Smiths Dock LLP | | 2014 |
| Smokes & Chill Ltd | Administrative & support | 2019 |
| Snodcombe Limited | Households | 1976 |
| Snowmac Homes Limited | Real estate | 2026 |
| Social Advantage Ltd | Professional & scientific | 2023 |
| Sofa to Saddle Ltd | Administrative & support | 2018 |
| Solan Trade Ltd | Transport & logistics | 2022 |
| Solar SOL Energy Ltd | Construction | 2023 |
| Solehub Limited | Wholesale & retail | 2021 |
| Solvi Jewellery Limited | Wholesale & retail | 2022 |
| Soma Movement Studio Ltd | Arts & recreation | 2026 |
| Sophie Grant Limited | Administrative & support | 2016 |
| Sourcedogg UK Limited | Information & communication | 2013 |
| South East Building Services (Kent) Ltd | Construction | 2022 |
| South East CNC Ltd | Manufacturing | 2018 |
| South East Contractors Ltd | Construction | 2019 |
| South East Flooring Limited | Construction | 2018 |
| South East Weight Loss Surgery Limited | Health & social care | 2022 |
| Southampton ROW Trust Limited | Financial services | 1999 |
| Southern Carpentry Limited | Construction | 1995 |