| Social Value Solutions Ltd | Information & communication | 2024 |
| SOL Consultants Limited | Real estate | 2020 |
| Solaris Print Ltd | Professional & scientific | 2017 |
| Sonke Limited | Wholesale & retail | 2013 |
| Sophie Evans Wine Ltd | Manufacturing | 2022 |
| Soul Suite Bar and Restaurant Ltd | Hospitality | 2018 |
| Sounds Lovely Limited | Professional & scientific | 2024 |
| Source BMX Ltd | Wholesale & retail | 2023 |
| South Coast Canine Academy Ltd | Other services | 2026 |
| South Coast Cargo Ltd | Other services | 2025 |
| South East Geomatics Ltd | Professional & scientific | 2016 |
| South East Plumbing & Gasworks Ltd | Construction | 2026 |
| Southeast Marketing Limited | Manufacturing | 2014 |
| Southern M & E Contractors Ltd | Construction | 2026 |
| Sovereign Residents Association Limited | Households | 1990 |
| Spanish Sand Ltd | Hospitality | 2022 |
| Sparkle & Shine Communal Cleaning Ltd | Administrative & support | 2026 |
| Sparklers Jewellery Limited | Wholesale & retail | 2014 |
| Speckled Wood Residents Association Limited | Real estate | 2025 |
| Spice Merchant Sussex Limited | Hospitality | 2018 |
| Spindle & Stag Properties Ltd | Real estate | 2025 |
| Sprocket Systems Ltd | Information & communication | 2025 |
| SS UK Retail Limited | Wholesale & retail | 2024 |
| SSC70 Ltd | Construction | 2026 |
| ST Aubyns (Bexhill) Limited | Professional & scientific | 2004 |
| ST James Private Finance Limited | Financial services | 1991 |
| ST John's Cloisters Company Limited | Households | 2003 |
| ST Leonards Ceramic Studio Ltd | Education | 2021 |
| ST Leonards Concerts CIC | Arts & recreation | 2025 |
| ST Leonards Motors (Holdings) Limited | Wholesale & retail | 2021 |
| ST Margarets Hastings Residents Association Limited | Households | 2008 |
| ST Michael's Hospice (Retail) Limited | Wholesale & retail | 1989 |
| ST. Helens Park Preservation Society Limited | Other services | 1960 |
| ST. James (Bexhill) Management Company Limited | Households | 2005 |
| ST. Seventy Seven Limited | Real estate | 2022 |
| St.John's House Residents Company Limited | Households | 1953 |
| St.Leonards Motors Limited | Wholesale & retail | 1960 |
| Stafford Court Limited | Households | 1974 |
| Standing OUT Standing Strong Ltd | Information & communication | 2026 |
| Stanmer Court Management Limited | Households | 1999 |
| Starbeans International Ltd | Manufacturing | 2023 |
| Static Home Sales Ltd | Wholesale & retail | 2021 |
| STB Pizza Ltd | Hospitality | 2022 |
| Steel Accountants Ltd | Professional & scientific | 2018 |
| Stella Murals Ltd | Arts & recreation | 2021 |
| Stewart Court (Bexhill) Management Limited | Households | 2011 |
| Stock Communications Design Food Limited | Arts & recreation | 2011 |
| Stonefield First Ltd | Construction | 2025 |
| Stoneford Limited | Professional & scientific | 2000 |
| Stories of Note Limited | Other services | 2018 |
| Strata 21 Limited | Professional & scientific | 1988 |
| Strathmore Court Limited | Households | 1970 |
| Strativeritas Limited | Information & communication | 2026 |
| Strensham Properties Limited | Real estate | 1989 |
| Stretton Park Management Limited | Households | 2019 |
| Stroud Property Maintenance Limited | Construction | 2025 |
| Stroud Roofing Ltd | Construction | 2024 |
| Studio D Photography Ltd | Professional & scientific | 2024 |
| Studio Matthew Holroyd Ltd | Professional & scientific | 2025 |
| Studio Playne Limited | Professional & scientific | 2024 |
| Studio Under the Sun Ltd | Arts & recreation | 2021 |
| Stunt 2025 Limited | Financial services | 2026 |
| Style Motors Limited | Wholesale & retail | 1983 |
| Style Pilgrim Ltd | Professional & scientific | 2024 |
| Sultan CAN Limited | Hospitality | 2017 |
| Summercourt (Hailsham) Limited | Households | 1982 |
| Sun Divin Limited | Wholesale & retail | 2020 |
| Sun Dog Drinks Ltd | Wholesale & retail | 2025 |
| Sun Union Limited | Extraterritorial | 2000 |
| Supreme Beauty Nails Ltd | Other services | 2025 |
| Surface Creative Limited | Administrative & support | 2007 |
| Sussex Coast Limited | Hospitality | 2021 |
| Sussex Concepts CIC | Wholesale & retail | 2016 |
| Sussex Fruits Ltd | Wholesale & retail | 2017 |
| Sussex Futsal Limited | Arts & recreation | 2017 |
| Sussex Renewables Ltd | Construction | 2022 |
| Sussex Safety Ltd | Other services | 2011 |
| Sussex Sound Ltd | Extraterritorial | 2020 |
| Sussex Vehicle Storage Limited | Transport & logistics | 2025 |
| Sussex View Hove Limited | Real estate | 2011 |
| SV Apps Ltd | Information & communication | 2026 |
| SWG Designs South East Ltd | Professional & scientific | 2019 |
| Sword Fixings Limited | Construction | 2011 |
| Swordfish Energy Ltd. | Energy | 2018 |
| SWS Home Improvements Limited | Administrative & support | 2017 |
| Syncardia Limited | Real estate | 2014 |
| System X Technologies Limited | Information & communication | 2025 |
| T & E Barrett Wealth Management Limited | Financial services | 2012 |
| T & R Partnership LLP | | 2004 |
| T Campbell Developments Ltd | Construction | 2022 |
| T Campbell Holdings Ltd | Financial services | 2022 |
| T Corp Ltd. | Information & communication | 2016 |
| T Daly Design Ltd | Administrative & support | 2014 |
| T&T Infinity Ltd | Hospitality | 2025 |
| T.M.T. Powder Coating Limited | Extraterritorial | 1980 |
| Table Flip Entertainment Ltd | Wholesale & retail | 2022 |
| Take IT Slow BBQ Ltd | Hospitality | 2023 |
| Talk and Build Ltd | Education | 2021 |
| Tamsin Limited | Information & communication | 2000 |
| Tasty Nosh Limited | Hospitality | 2018 |