| Scenna & Associates Limited | Professional & scientific | 2008 |
| Scott Maynard Plastering Limited | Construction | 2011 |
| Scott Richardson Coaching Limited | Extraterritorial | 2020 |
| Screaming Colour Limited | Manufacturing | 2008 |
| SD Infosec Ltd | Information & communication | 2025 |
| SD Management Consultants Limited | Construction | 2016 |
| SDL Detailing Ltd | Professional & scientific | 2021 |
| Seaforth Court (Eastbourne) RTM Company Limited | Households | 2014 |
| Seaforth Court Freehold Ltd | Administrative & support | 2017 |
| Seahorse Estates Ltd | Real estate | 2012 |
| Sebo Consultancy Ltd | Professional & scientific | 2023 |
| Second Nature Careers Limited | Education | 2025 |
| SEG South East Ltd | Construction | 2025 |
| Segmantics Ltd. | Information & communication | 2013 |
| Segment Innovation Ltd | Construction | 2020 |
| Selborne Advisory Limited | Professional & scientific | 2021 |
| SELFSTORAGE1999 - UK Ltd | Financial services | 2021 |
| Sell an Asset Limited | Information & communication | 2003 |
| Sentinex Limited | Information & communication | 2025 |
| Sephirot East Point Ltd | Manufacturing | 2017 |
| Serigraphics Limited | Administrative & support | 2019 |
| Servante Studio Limited | Other services | 2003 |
| Seva Group Limited | Wholesale & retail | 2022 |
| Seymour & Benson Limited | Real estate | 2026 |
| Seymour Yachts Ltd | Wholesale & retail | 2020 |
| Shared Sector Consulting Ltd | Information & communication | 2023 |
| Sheelvanth Properties Ltd | Real estate | 2023 |
| Shieldburn Property Ltd | Real estate | 2009 |
| Shindzela Investments Limited | Financial services | 2021 |
| Shrooly Ltd | Wholesale & retail | 2022 |
| Shrubbs IT Services Limited | Information & communication | 2015 |
| Shuretech Holdings Limited | Financial services | 2020 |
| Shuretech Limited | Administrative & support | 2011 |
| Shutter-Man South East Limited | Wholesale & retail | 2017 |
| Silver Garden Ltd | Administrative & support | 2015 |
| Silverfish Software Ltd | Wholesale & retail | 2025 |
| Silveroaks Forestry Ltd | Agriculture & fishing | 2021 |
| Simple Everyday Ltd | Wholesale & retail | 2014 |
| Simply Accounts Partners Ltd | Information & communication | 2011 |
| Simply Accounts Partnership LLP | | 2011 |
| Simply Bengal Ltd | Hospitality | 2024 |
| Sincroll Drive Technologies Ltd | Manufacturing | 2008 |
| Single-Ply Roofing Consultants Ltd | Construction | 2024 |
| SIX String Consulting Ltd | Professional & scientific | 2019 |
| SJM Commercial Ltd | Professional & scientific | 2022 |
| SJP Accountancy Ltd | Professional & scientific | 2017 |
| SJS Consultancy Services Ltd | Administrative & support | 2023 |
| Skill Visage Limited | Health & social care | 2018 |
| Sky High Trampoline Gymnastics Academy | Arts & recreation | 2013 |
| Slawwo G. B. Ltd | Construction | 2023 |
| SLP Consulting & Training Limited | Administrative & support | 2011 |
| SLT Services Ltd | Wholesale & retail | 2015 |
| Smarter Home Electrics Ltd | Construction | 2018 |
| Smartmore Ltd | Information & communication | 2016 |
| Smiler & Big Dog Ltd | Real estate | 2017 |
| Smithers Barn Cookery School Ltd | Hospitality | 2023 |
| Snowhart Limited | Professional & scientific | 2008 |
| Social Tender Consultancy Ltd | Professional & scientific | 2017 |
| Solaris Exploration Limited | Mining & quarrying | 2009 |
| Soleli Ltd | Manufacturing | 2025 |
| Solilah-Rae Limited | Wholesale & retail | 2024 |
| Solution & Services Ltd | Wholesale & retail | 2024 |
| Sonec Wise CIC | Professional & scientific | 2023 |
| Song Solutions Limited | Information & communication | 1992 |
| South Brockwells Farm Shop Ltd | Wholesale & retail | 2020 |
| South Park (Bexhill) Management Limited | Real estate | 1998 |
| Southern Catering Limited | Hospitality | 2022 |
| Southern Resin Solutions Ltd | Construction | 2022 |
| Southlands Road Bexhill Limited | Construction | 2026 |
| Southon Property Maintenance Ltd | Construction | 2014 |
| SP Resin Solutions Ltd | Construction | 2025 |
| Spa Therapy Ltd | Other services | 2018 |
| Spartan Boss Ltd | Professional & scientific | 2018 |
| Spartan Operations Limited | Public administration | 2020 |
| Spartan Precision Equipment Limited | Professional & scientific | 2012 |
| Spasov Property Investments Ltd | Real estate | 2025 |
| Spatacular Limited | Wholesale & retail | 2008 |
| Special Needs Family Support Limited | Health & social care | 2010 |
| Specialized Driving Force Limited | Transport & logistics | 1997 |
| Speed Cubes Limited | Wholesale & retail | 2022 |
| Spice Fusion (Uckfield) Limited | Hospitality | 2010 |
| Split Share Limited | Real estate | 2017 |
| Sport & Play Installation Manufacture Services Limited | Arts & recreation | 2015 |
| Sport & Play Limited | Arts & recreation | 2006 |
| Sportskinetic Ltd | Extraterritorial | 2026 |
| Spring Harvest Holidays Limited | Administrative & support | 2012 |
| Spring Physio Ltd | Health & social care | 2018 |
| Springfields Biodynamic Vineyard Limited | Agriculture & fishing | 2018 |
| Springpoint Construction Limited | Construction | 2015 |
| SRN Systems Ltd | Professional & scientific | 2016 |
| SSC Holdings Limited | Professional & scientific | 2000 |
| ST Clears Corporate Services Ltd | Professional & scientific | 2015 |
| ST James' Lodge RTM Company Limited | Households | 2014 |
| ST. Mary's Mead Management Company Limited | Households | 1996 |
| Stag Business Services Limited | Administrative & support | 2022 |
| Stages Work Experience Programme Ltd | Wholesale & retail | 2020 |
| Stainless Agri Ltd | Wholesale & retail | 2024 |
| Standenld Bilston Limited | Construction | 2017 |
| Star Plant Ltd | Construction | 2017 |
| Star Pool Enclosure Ltd | Construction | 2019 |