| Serenity Lakes Ltd | Construction | 2019 |
| Serenity Wealth Management Ltd | Professional & scientific | 2024 |
| Serious About Competitive Tennis Ltd | Arts & recreation | 2023 |
| Serious About Sport Ltd | Arts & recreation | 2020 |
| Seven Construction Southern Ltd | Construction | 2025 |
| Shammy Shack Limited | Wholesale & retail | 2012 |
| Sharp Reflections Ltd | Professional & scientific | 2014 |
| Shear Architectural Design Limited | Professional & scientific | 2017 |
| Shepheard Property Holdings Ltd | Real estate | 2022 |
| Sherry Services Ltd | Wholesale & retail | 2023 |
| Shift IT Property Solutions Limited | Real estate | 2019 |
| Shine Sisters Cleaning Ltd | Administrative & support | 2023 |
| Shires Electrics Limited | Construction | 2021 |
| Shoottv Group Ltd | Information & communication | 2025 |
| Shore CUT Construction Ltd | Manufacturing | 2023 |
| Shore Therapy Ltd | Wholesale & retail | 2010 |
| Shore Welding Limited | Manufacturing | 2021 |
| Shoreham Construction (Southern) Limited | Construction | 2009 |
| Shoreham FC 2013 Limited | Arts & recreation | 2013 |
| Shoreham Football Academy Ltd | Arts & recreation | 2019 |
| Shoreham Networks Limited | Information & communication | 2007 |
| Shoreham Rugby Football Club Ltd | Arts & recreation | 2014 |
| Shoreham Vehicle Auctions Limited | Wholesale & retail | 1993 |
| Shoreline Aggregates Ltd | Wholesale & retail | 2026 |
| Short Holdings Limited | Financial services | 2018 |
| Shout Music Publishing Ltd | Extraterritorial | 2012 |
| Shyqyri Ltd | Administrative & support | 2020 |
| Silver Beach Developments Limited | Construction | 2003 |
| Silver Beach Properties Limited | Real estate | 2003 |
| Silver Lining (O.T.S.) Limited | Information & communication | 2018 |
| Simba Holdings Limited | Professional & scientific | 2008 |
| Simon Buckman Carpentry Ltd | Construction | 2022 |
| Simon Sweet Limited | Construction | 2002 |
| Simonds Associates Ltd | Professional & scientific | 2012 |
| Simplex Limited | Manufacturing | 1988 |
| Sing and Sign Ltd. | Information & communication | 2001 |
| Singers Roofing Ltd | Construction | 2021 |
| Sirocoss Consultants Ltd | Professional & scientific | 2017 |
| Site Team Projects Limited | Construction | 2023 |
| SJT Property Ltd | Real estate | 2019 |
| SKB Healthcare Limited | Health & social care | 2019 |
| Skilltorch Ltd | Administrative & support | 2022 |
| Skoff Ltd | Extraterritorial | 2015 |
| Skyquest Aerospace Ltd | Extraterritorial | 2021 |
| Skyrise South Scaffolding Ltd | Construction | 2024 |
| Skyward Productions Ltd | Transport & logistics | 2017 |
| Sleh Consulting Limited | Administrative & support | 2023 |
| Sleh Limited | Administrative & support | 2022 |
| Smart Construction (Sussex) Limited | Construction | 2000 |
| Smartwood Flooring (Sussex) Limited | Extraterritorial | 2024 |
| Smashndash Ltd | Hospitality | 2025 |
| SMN Planning & Development Support Ltd | Professional & scientific | 2026 |
| SN3PAL Ltd | Wholesale & retail | 2022 |
| Snip ITZ Ltd | Other services | 2017 |
| SNJ Electrical Limited | Manufacturing | 2014 |
| Social Care Advice Ltd | Health & social care | 2000 |
| Solomay Ltd | Education | 2026 |
| Something Blue Events Ltd | Arts & recreation | 2023 |
| Sompting Abbotts School Limited | Education | 1946 |
| Sompting Direct Ltd | Hospitality | 2018 |
| Sooty Holdings Ltd | Professional & scientific | 2025 |
| South Coast Electronics Limited | Manufacturing | 1967 |
| South Coast Funeral Support Ltd | Other services | 2023 |
| South Coast Rods Limited | Wholesale & retail | 2018 |
| South Coast Soccer Academy Ltd | Manufacturing | 2022 |
| South Eastern Construction Limited | Real estate | 2004 |
| South Shore Air Conditioning and Refrigeration Ltd | Manufacturing | 2021 |
| South Signs Limited | Professional & scientific | 2020 |
| South Terranova Ltd | Information & communication | 2023 |
| Southdown Kitchen Furniture Limited | Manufacturing | 2008 |
| Southern Claims Management Ltd | Administrative & support | 2023 |
| Southern Fresh Flowers Limited | Wholesale & retail | 2014 |
| Southern Services Group Ltd | Transport & logistics | 2017 |
| Southern Services Ltd | Construction | 2016 |
| Southshore Construction Limited | Construction | 2026 |
| SPD Contract Management Limited | Professional & scientific | 2021 |
| Spice Cafe & Bar Ltd. | Hospitality | 2025 |
| Spray Shop Architectural Limited | Manufacturing | 2017 |
| Spruce Gardening & Tree Care Limited | Administrative & support | 2022 |
| SPV Holdings Limited | Real estate | 2016 |
| ST Nicholas Court RTM Company Ltd | Households | 2014 |
| ST. Giles Properties Limited | Real estate | 1974 |
| Steele Groundworks and Civil Engineering Ltd | Administrative & support | 2024 |
| Stenning Mulcare Ltd | Professional & scientific | 2019 |
| Stitch & Shout UK Ltd | Wholesale & retail | 2025 |
| Stocks House Freeholders Association Ltd | Extraterritorial | 1961 |
| Storix Ltd | Transport & logistics | 2025 |
| Strenson Fitness Ltd | Arts & recreation | 2019 |
| Strenson Holdings Limited | Financial services | 2018 |
| Stripey Lemon Ltd | Administrative & support | 2018 |
| Stuart Douch Graphic Art Ltd | Information & communication | 2023 |
| Studio 1994 Ltd | Information & communication | 2025 |
| Studio Fractal Holdings Ltd | Financial services | 2024 |
| Studio Fractal Ltd | Professional & scientific | 2014 |
| Studio Hatch Limited | Arts & recreation | 2022 |
| Studio Moule Ltd | Professional & scientific | 2026 |
| Sula Clothing Limited | Wholesale & retail | 2006 |
| Sullivan Software Solutions Ltd | Information & communication | 2025 |
| Summit Social Ltd | Professional & scientific | 2024 |
| Sunic Limited | Wholesale & retail | 2021 |