| SAM Goldie Ltd | Professional & scientific | 2014 |
| Sandhurst Food & Beverages Limited | Hospitality | 2024 |
| Sandringham Lodge Residents RTM Company Limited | Households | 2006 |
| Santana Motorworks Limited | Wholesale & retail | 2024 |
| Sarah Breakwell VFX Limited | Information & communication | 2018 |
| Sarah O'Donoghue Conservation Limited | Manufacturing | 2017 |
| Sarah's Hair Limited | Other services | 2016 |
| SAS Locums Limited | Health & social care | 2002 |
| Sash Window Restoration Sussex Limited | Construction | 2016 |
| Sash Window Restorations (Sussex) Ltd | Other services | 2011 |
| Saxons Construction Ltd | Construction | 2023 |
| Scacco Matto Limited | Hospitality | 2001 |
| School Wellbeing Cards Limited | Wholesale & retail | 2022 |
| SCT Trading Limited | Hospitality | 2019 |
| Seacraft IT Limited | Transport & logistics | 2025 |
| Seawild Ltd | Agriculture & fishing | 2020 |
| Secret Cabins Limited | Hospitality | 2020 |
| Selby Lodge (Freehold) Limited | Households | 2018 |
| Selby Lodge RTM Company Limited | Households | 2019 |
| Sensational Places Limited | Real estate | 2023 |
| Sensational Spaces Limited | Construction | 2019 |
| Sepia Design Limited | Professional & scientific | 1998 |
| Seraphim Laundry Ltd | Other services | 2022 |
| Seratis Hypnotherapy Ltd | Health & social care | 2026 |
| Shark Helicopters Ltd | Transport & logistics | 2015 |
| Shearers Accountants Ltd | Professional & scientific | 2014 |
| Sheet Metal Express Ltd | Manufacturing | 2025 |
| SHEET2SITE Ltd | Information & communication | 2021 |
| Sheppard Properties Limited | Real estate | 2015 |
| Sherwood Manchester Peck Ltd | Manufacturing | 2020 |
| Shingletech Ltd | Information & communication | 2019 |
| Shizzy Little Space Ltd | Arts & recreation | 2026 |
| Shore Endeavours Limited | Real estate | 2015 |
| Shore Health Physio Ltd | Other services | 2023 |
| Shore PBS Ltd | Construction | 2022 |
| Shore TAN Limited | Other services | 2024 |
| Shoreham Bathrooms Limited | Construction | 2024 |
| Shoreham Cafe Ltd | Hospitality | 2017 |
| Shoreham Caters Limited | Hospitality | 2023 |
| Shoreham Helicopters Ltd | Transport & logistics | 2008 |
| Shoreham Luxe Cleaning Ltd | Administrative & support | 2025 |
| Shoreham Marine Consulting Ltd | Extraterritorial | 2024 |
| Shoreham Market Ltd | Wholesale & retail | 2025 |
| Shoreham Payroll Service Limited | Administrative & support | 2003 |
| Shoreham Pottery Ltd | Education | 2024 |
| Shoreham Pubs Ltd | Hospitality | 2013 |
| Shorehamlandscapingcontractors Ltd | Administrative & support | 2023 |
| Shoreline Marine Services (Sussex) Ltd | Manufacturing | 2025 |
| Shoreline Projects (Sussex) Ltd | Construction | 2022 |
| Shoreline Skips Ltd | Water & waste | 2026 |
| Shoreshot Construction Limited | Construction | 2024 |
| Shoreshot Design and Build LLP | | 2023 |
| Sigta Limited | Education | 1974 |
| Silkwood Traders Limited | Wholesale & retail | 2010 |
| Silver Lining Convergence Ltd | Information & communication | 2007 |
| Silver Sunset Limited | Financial services | 2012 |
| Silver Sunset Subsidiary Limited | Wholesale & retail | 2012 |
| Silver Web Services Limited | Information & communication | 2007 |
| Simon Hick Limited | Information & communication | 2018 |
| Simon Wilson Plumbing Services Ltd | Construction | 2015 |
| Sincerity School C.I.C. | Education | 2025 |
| Single FIN Construction Ltd | Construction | 2025 |
| SIX at Sixty Five Limited | Households | 1989 |
| SJL Entertainment Ltd | Hospitality | 2024 |
| SK Eagle Management Limited | Professional & scientific | 2025 |
| SKJ Touring Limited | Arts & recreation | 2026 |
| Skye Light Ltd | Construction | 2018 |
| Skylined Limited | Professional & scientific | 2013 |
| Slrbrighton Ltd | Real estate | 2020 |
| Slts of Colour Ltd | Information & communication | 2022 |
| Smart Green Electrical Ltd | Construction | 2022 |
| Smart Transport Transfers Limited | Transport & logistics | 2026 |
| SMG NDT Ltd | Manufacturing | 2015 |
| SMG NDT Motorsport Ltd | Professional & scientific | 2022 |
| Smhp Consultancy Ltd | Professional & scientific | 2018 |
| SMR Property Investments Ltd | Real estate | 2024 |
| Smudge INK Limited | Wholesale & retail | 2013 |
| Socraates Technologies Ltd | Information & communication | 2022 |
| Solar Storm Entertainment Ltd | Information & communication | 2013 |
| Sole & Sail Ltd | Wholesale & retail | 2025 |
| Soley Cleaning and Linen Services Ltd | Administrative & support | 2024 |
| Solution Sussex Ltd | Professional & scientific | 2014 |
| Sonsgifting Ltd | Wholesale & retail | 2025 |
| Souk IT and SEE Ltd | Wholesale & retail | 2022 |
| Soulshine Digital Ltd | Professional & scientific | 2025 |
| Sound Solutions Products Limited | Manufacturing | 2004 |
| Soundwright Ltd | Information & communication | 2025 |
| Sourcing Ventures Limited | Administrative & support | 2022 |
| South Coast Developments (Sussex) Limited | Professional & scientific | 2015 |
| South Coast PHV Hire Limited | Administrative & support | 2026 |
| South Coast Tree Care Ltd | Agriculture & fishing | 2014 |
| South Court (Brighton) Management Company Limited | Households | 2014 |
| South Downs Farming Enterprises Ltd | Agriculture & fishing | 2018 |
| South East Addiction & Recovery Services CIC | Hospitality | 2025 |
| South West Communications Group Holdings Limited | Professional & scientific | 2005 |
| South West Communications Group Limited | Information & communication | 1984 |
| Southdown Car Sales Limited | Wholesale & retail | 1962 |
| Southdown House (Hove) RTM Company Limited | Households | 2013 |
| Southdowns Plumbing & Heating Limited | Construction | 2023 |
| Southern Coastal Developments Ltd | Real estate | 2017 |