| Shropshire Container Services Limited | Information & communication | 2002 |
| SI Property Group Limited | Real estate | 2020 |
| Siamese Trading Ltd | Wholesale & retail | 2015 |
| Siena Drive Management Company Limited | Administrative & support | 2006 |
| SIF Curry House Limited | Hospitality | 2025 |
| Signigene Limited | Health & social care | 2021 |
| Silva DA Rosa Ltd | Transport & logistics | 2017 |
| Silvercare (UK) Limited | Wholesale & retail | 2011 |
| Simon King Construction Limited | Construction | 1993 |
| Simon Markos Vreony Ltd | Extraterritorial | 2025 |
| Simple Startup Limited | Administrative & support | 2012 |
| Simply Extras Limited | Administrative & support | 2004 |
| Simply Ginger Ltd | Professional & scientific | 2024 |
| Simpsons Coffee and More Ltd | Hospitality | 2025 |
| Simwon Property Co.Limited | Real estate | 1962 |
| Simwon Property Ventures Limited | Real estate | 2026 |
| Sing & Play Ltd | Arts & recreation | 2024 |
| SIP Bite & Taste Ltd | Other services | 2026 |
| SIR John Moore Court (Sandgate) Limited | Households | 2005 |
| Sire JB Ltd | Health & social care | 2026 |
| Sirocco 25 Limited | Construction | 2025 |
| Siski Support Ltd | Administrative & support | 2021 |
| Site Labour Supplies Group Ltd | Administrative & support | 2020 |
| Site Labour Supplies Limited | Administrative & support | 2007 |
| Site Performance Art CIC | Arts & recreation | 2022 |
| Siwa Properties Ltd | Real estate | 2017 |
| SIX05 Fabriks and Fits Limited | Other services | 2025 |
| SJ Harmony Homes Ltd | Real estate | 2024 |
| SJ Ruthwell Limited | Real estate | 2026 |
| SK Developments SPV 1 Ltd | Real estate | 2024 |
| Skanda Hythe Ltd | Hospitality | 2019 |
| Skane Ltd | Hospitality | 2025 |
| Skipta Consulting Limited | Professional & scientific | 2016 |
| Sks-Pub Managment Ltd | Hospitality | 2022 |
| Skyfotos Limited | Professional & scientific | 1989 |
| Slater & Lucey Building Co Ltd | Construction | 2023 |
| Sleeping Giant Media Limited | Professional & scientific | 2008 |
| SLF Body Clinic Ltd | Arts & recreation | 2022 |
| Slvr Hairdressing Limited | Other services | 2019 |
| Small Cars Kent Limited | Wholesale & retail | 2021 |
| Smart Marketing Support Ltd | Administrative & support | 2014 |
| Smeeth Holdings Limited | Other services | 2011 |
| Smith Woolley (Folkestone) LLP | | 2023 |
| Smith's MOT Contractor Limited | Wholesale & retail | 2025 |
| SML Matt Large Ltd | Construction | 2016 |
| SMM & BJM Enterprises Ltd | Wholesale & retail | 2025 |
| Smokey Tones Ltd | Hospitality | 2023 |
| Snugalo Ltd | Wholesale & retail | 2023 |
| Snuggle Games Ltd | Manufacturing | 2023 |
| Social Media for Schools Limited | Professional & scientific | 2020 |
| Social Systems Change Advisory Ltd | Professional & scientific | 2026 |
| Socialmarketing Ltd | Professional & scientific | 2024 |
| Sock Supply Ltd | Wholesale & retail | 2025 |
| Sole Kitchen Ltd | Wholesale & retail | 2017 |
| Solhan Estate Limited | Real estate | 2021 |
| Solomon Elegant Properties Ltd | Hospitality | 2023 |
| Sophea Liles-Bailey Costume Ltd | Professional & scientific | 2025 |
| Soul Health and Recovery Ltd | Health & social care | 2012 |
| Sound Light Solutions Limited | Information & communication | 2021 |
| South Coast Fencing & Landscaping Ltd | Administrative & support | 2025 |
| South East Kent Property Limited | Real estate | 2014 |
| South East Storage Limited | Transport & logistics | 2024 |
| South Kent Community Church | Other services | 1996 |
| South Kent Developments Ltd | Real estate | 2020 |
| South Kent Mind Ltd | Health & social care | 2001 |
| Southey Construction Ltd | Construction | 2025 |
| Southstone Court Management Limited | Households | 2001 |
| Space Cowboy Vintage Ltd | Wholesale & retail | 2025 |
| Spearman Testing Services Ltd | Manufacturing | 2025 |
| Special Events Crew Limited | Arts & recreation | 2018 |
| Specialist Driver Solutions Ltd | Administrative & support | 2024 |
| Spenhill Property Management Limited | Households | 1997 |
| Sphinx Renovatie Ltd | Construction | 2007 |
| Spice HUT Kitchen Ltd | Hospitality | 2025 |
| Spicer's Court Management Company Limited | Households | 1991 |
| Spire Media Group Limited | Professional & scientific | 2020 |
| Spire Property Ltd | Construction | 2019 |
| Spitfire Glazing Ltd | Construction | 2025 |
| Sports Tracker Ltd | Information & communication | 2026 |
| Spot on Tiling Limited | Construction | 2008 |
| Sprettynice Ltd | Information & communication | 2010 |
| Springers Personalised Products Limited | Wholesale & retail | 2009 |
| Spud Club Limited | Hospitality | 2025 |
| Spyder Forensics Ltd | Education | 2019 |
| Squirrel Squared Limited | Information & communication | 2009 |
| Sridevi Limited | Information & communication | 2018 |
| Srpk Limited | Wholesale & retail | 2025 |
| SRS Management Limited | Real estate | 1996 |
| Ssai Properties Ltd | Real estate | 2024 |
| SSF Building & Maintenance Limited | Construction | 2021 |
| SSL Housing & Social Care Consultancy Services Ltd | Professional & scientific | 2016 |
| ST Augustine's Property Ltd | Real estate | 2020 |
| ST Eanswythe's Church of England Primary School | Education | 2013 |
| ST Johns Church RD (Folkestone) Ltd | Households | 2019 |
| ST Malo Property Management Limited | Households | 2019 |
| ST. Martin's Cheriton Community Centre Ltd. | Other services | 2011 |
| Stable Fire Protection Limited | Manufacturing | 2011 |
| Standen Storage Limited | Administrative & support | 2024 |
| Stanfords Ltd | Construction | 2024 |
| Stapley Mortgages Ltd | Financial services | 2014 |