| STF Clothing Ltd | Wholesale & retail | 2019 |
| STH Construction Limited | Construction | 2004 |
| Stillwell Services Ltd | Wholesale & retail | 2026 |
| Stirling Hill Limited | Financial services | 2021 |
| Stitchcraft With Donna Munday Limited | Professional & scientific | 2019 |
| STM Electrical Services Ltd | Other services | 2019 |
| Stock Shutters Ltd | Manufacturing | 2018 |
| Stoneage Roofing Specialists Ltd | Construction | 2022 |
| Stoneway Contracting Co. Limited | Construction | 1986 |
| Strata Risk Intelligence Ltd | Information & communication | 2026 |
| Stratagem Energy Consulting Limited | Professional & scientific | 2026 |
| Strawbs of Bognor Limited | Transport & logistics | 2024 |
| Strongbox Solutions Ltd | Administrative & support | 2026 |
| Studio Dog Ltd | Professional & scientific | 2023 |
| Studio SIX Hair & Beauty Limited | Other services | 2023 |
| Studio Southsea Interior Services Ltd | Professional & scientific | 2024 |
| Stype Consulting Limited | Information & communication | 2016 |
| SUBAITA16 Ltd | Hospitality | 2017 |
| Subjecttochange Ltd | Arts & recreation | 2014 |
| Suharevs Transport Ltd | Transport & logistics | 2022 |
| Suhrad Services Ltd | Wholesale & retail | 2021 |
| Summerley Business Solutions Limited | Administrative & support | 2017 |
| Summerley Dental Practice Limited | Health & social care | 2006 |
| Summerley Estate Management Company Ltd | Households | 2020 |
| Summerley Gate Residents Management Company Limited | Households | 2013 |
| Summersea Limited | Households | 1986 |
| Sun-X (United Kingdom) Limited | Construction | 1978 |
| Suncourt Villas RTM Company Limited | Households | 2013 |
| Sundale Lane Residents Association Limited | Households | 1989 |
| Sunnyfields Holdings Limited | Real estate | 1958 |
| Sunnyside Holdings Limited | Construction | 2017 |
| Suns UP Entertainment Limited | Arts & recreation | 2022 |
| Supellex Ltd | Wholesale & retail | 2024 |
| Super Mario Transport Ltd | Construction | 2023 |
| Supercharged Food UK Ltd | Wholesale & retail | 2022 |
| Supernatural X Ltd | Manufacturing | 2018 |
| Supersigns Graphics Limited | Real estate | 1990 |
| Supplybee Ltd | Administrative & support | 2024 |
| Support Plus Limited | Real estate | 1994 |
| Surelook Paralegal Systems Ltd | Information & communication | 2025 |
| Surface Solutions Designs Ltd | Professional & scientific | 2025 |
| Surface Solutions Southern Ltd | Construction | 2025 |
| Surrey Wharf Arundel Limited | Households | 1999 |
| Survival 2 Significance Ltd | Professional & scientific | 2020 |
| Sussex Accountancy and Payroll Services Ltd | Professional & scientific | 2008 |
| Sussex Building Consultancy Limited | Professional & scientific | 2003 |
| Sussex Ceilings Limited | Construction | 2016 |
| Sussex Cleaning Services Ltd | Administrative & support | 2011 |
| Sussex Cruise Club Limited | Administrative & support | 2008 |
| Sussex Electrical Care Ltd | Administrative & support | 2016 |
| Sussex Engine Supplies Limited | Wholesale & retail | 1977 |
| Sussex Estate Care Limited | Other services | 2015 |
| Sussex Flint & Stonemason Co. Limited | Manufacturing | 2014 |
| Sussex Fryer Bognor Regis Butlins Limited | Hospitality | 2021 |
| Sussex GIN Girl Ltd | Wholesale & retail | 2019 |
| Sussex Hampshire Surrey Scaffolding Ltd | Construction | 2024 |
| Sussex Haulage Limited | Transport & logistics | 2024 |
| Sussex Media Marketing Limited | Professional & scientific | 2025 |
| Sussex Pets & Exotics Limited | Wholesale & retail | 2024 |
| Sussex Property Care Ltd | Construction | 2024 |
| Sussex React Ltd | Construction | 2018 |
| Sussex Reeves Home Ltd | Construction | 2011 |
| Sussex Renovations Construction Limited | Construction | 2005 |
| Sussex SAR for Lost Dogs CIC | Agriculture & fishing | 2022 |
| Sussex Shoes Limited | Wholesale & retail | 2005 |
| Sussex Smiles Ltd | Health & social care | 2025 |
| Sussex Therapies & Hypnosis Ltd | Health & social care | 2022 |
| Sussex Toilets Limited | Administrative & support | 2015 |
| Sussex Vehicle Solutions Ltd | Wholesale & retail | 2022 |
| Sussex Woodburners Ltd | Wholesale & retail | 2020 |
| Sustainable Development Foundation | Professional & scientific | 2005 |
| Sustainable Futures Trust | Extraterritorial | 2020 |
| Sutcliff Consultants Limited | Professional & scientific | 2003 |
| SVB Transport Limited | Transport & logistics | 2016 |
| Swallows Gate Management Company Limited | Households | 2021 |
| Swami Retail Ltd | Wholesale & retail | 2019 |
| Swan Court Residents' Association Ltd | Households | 2019 |
| Swanbourne Construction Ltd | Construction | 2025 |
| Swann Electrical Services Ltd | Construction | 2020 |
| Sweep and Sparkle Limited | Administrative & support | 2019 |
| Sweet Dream Foods Limited | Manufacturing | 2022 |
| Sweet Tingz Ltd | Hospitality | 2025 |
| Swift Liquid Screeds Limited | Construction | 2022 |
| SY3 Design Ltd | Professional & scientific | 2020 |
| Synthetic Data Ltd | Information & communication | 2017 |
| Systemic Technology Limited | Information & communication | 2009 |
| SZB Southern Electrical Ltd | Construction | 2024 |
| T Ashcroft Property Ltd | Real estate | 2024 |
| T Wydra Composites Ltd | Manufacturing | 2024 |
| T&C Electrical (Southern) Ltd | Construction | 2012 |
| T&M Rentals Limited | Real estate | 2025 |
| T.H Barbering Ltd | Other services | 2023 |
| T4 Property Management Ltd | Real estate | 2024 |
| TA Electrical Services Ltd | Construction | 2022 |
| Tackles OUT Fishing Supplies Ltd | Wholesale & retail | 2025 |
| Tagoro Consulting Limited | Information & communication | 2018 |
| Taico Limited | Real estate | 2009 |
| TAN ME Ltd | Other services | 2025 |
| Tandoori Takeaway Barnham Limited | Hospitality | 2022 |
| TAP & Flow Services Ltd | Water & waste | 2025 |