| S H Flooring (Sussex) Ltd | Construction | 2018 |
| S H H Limited | Other services | 2005 |
| S I a Plumbing and Heating Services Limited | Construction | 2002 |
| S J Slade Enterprises Limited | Information & communication | 2026 |
| S M Cleaning (Worthing) Ltd | Administrative & support | 2018 |
| S M P Couriers Limited | Transport & logistics | 2009 |
| S N Jaman Ltd | Hospitality | 2020 |
| S Orford Heating Limited | Construction | 2016 |
| S P Plant Hire Limited | Construction | 2019 |
| S Phillips Plumbing and Heating Ltd | Construction | 2017 |
| S R Courier Worthing Limited | Transport & logistics | 2018 |
| S R Crunden Electrical Contractors Limited | Construction | 2011 |
| S R H Interiors Limited | Construction | 2016 |
| S R Moon Fashion Limited | Administrative & support | 2018 |
| S T Industries Limited | Information & communication | 2022 |
| S&L Design Limited | Information & communication | 2020 |
| S&L Key Cutting Ltd | Wholesale & retail | 2024 |
| S&W Property Investment Group Limited | Real estate | 2024 |
| S.E.C. Property Development Limited | Construction | 1988 |
| S.H.E.R. Management Consultants Ltd | Administrative & support | 2014 |
| S.Hutchins & Green Limited | Construction | 1934 |
| S.L.H Construction (Sussex) Ltd | Construction | 2017 |
| SA Futures Limited | Real estate | 2022 |
| Saang Consulting Limited | Information & communication | 2015 |
| Saansid UK Limited | Professional & scientific | 2025 |
| Saba Trade Ltd | Wholesale & retail | 2020 |
| Saber Digital Ltd | Other services | 2017 |
| Sabey Court Maintenance Company Limited | Households | 1981 |
| Sabre Stone Limited | Manufacturing | 2006 |
| Sacco-Thomas Limited | Construction | 2024 |
| Safcol(Europe)Limited | Administrative & support | 1983 |
| Safe Cool Ltd | Manufacturing | 2023 |
| Safe Homes Windows Sussex Limited | Construction | 2021 |
| Safego Ltd | Real estate | 2007 |
| Safeguard Fire Doors Limited | Construction | 2025 |
| Safety Distinction UK Limited | Administrative & support | 2025 |
| Safety Metal Window Repair Co Limited | Construction | 2004 |
| Safety Mode Limited | Education | 2016 |
| Safety Supply Wholesale Ltd | Wholesale & retail | 2020 |
| Safeview Windows (Sussex) Limited | Construction | 2011 |
| Saffron Barker Ltd | Other services | 2017 |
| Saffron DSG LLP | | 2006 |
| Safy Transport Ltd | Transport & logistics | 2019 |
| Sage Grocers Ltd | Wholesale & retail | 2024 |
| Sahand Limited | Real estate | 2014 |
| SAI Cash & Carry (Sussex) Limited | Wholesale & retail | 2006 |
| Saint Aero Limited | Transport & logistics | 2026 |
| Saint Physiotherapy Ltd | Health & social care | 2006 |
| Saku Studios Ltd | Other services | 2022 |
| SAL Property Investments Ltd | Real estate | 2025 |
| SAL Women's Health Clinic Limited | Health & social care | 2017 |
| Salad OR Chips Ltd | Hospitality | 2020 |
| Salbright Consultants Limited | Real estate | 1986 |
| Saldia Limited | Financial services | 2014 |
| SALE2ALL Ltd | Wholesale & retail | 2026 |
| Salient Creative Collective Ltd | Professional & scientific | 2023 |
| Salix Analytics Ltd | Information & communication | 2025 |
| Sally Works Here Ltd | Arts & recreation | 2021 |
| Salon Secrets Sussex Limited | Other services | 2014 |
| Salt Raiders Ltd | Information & communication | 2020 |
| Salt Renovations Ltd | Construction | 2024 |
| Salty & Sweet Ltd | Hospitality | 2025 |
| Salty Productions Ltd | Information & communication | 2024 |
| SAM Devlin Consulting Ltd | Professional & scientific | 2025 |
| SAM Osborne Glazing Ltd | Construction | 2024 |
| SAM Spice Construction Ltd | Construction | 2019 |
| Sam-Culture Limited | Arts & recreation | 2014 |
| Samara Property Limited | Real estate | 2025 |
| Samaria Developments Limited | Other services | 2019 |
| Samaria Holdings Limited | Other services | 2019 |
| Samber Investments Limited | Real estate | 2022 |
| Same US Ltd | Hospitality | 2025 |
| Samham Limited | Information & communication | 2022 |
| Sami-Hm Ltd | Education | 2025 |
| Samm Commerce Limited | Wholesale & retail | 2020 |
| Sampson Eco Limited | Administrative & support | 2019 |
| Samson Web Design Limited | Information & communication | 2011 |
| Samuel Justice Sound Ltd | Information & communication | 2014 |
| Samurai Law Ltd | Professional & scientific | 2019 |
| Sanae Floyd Coaching Ltd | Professional & scientific | 2020 |
| Sanctuary Brew Co Ltd | Wholesale & retail | 2020 |
| Sandena Homes Limited | Construction | 2006 |
| Sandena Square Management Company Limited | Households | 2004 |
| Sandon Homes Limited | Real estate | 1996 |
| Sandra Prail Limited | Other services | 2013 |
| Sandstone Projects Ltd | Construction | 2025 |
| Sandsys Limited | Professional & scientific | 2003 |
| Sane UX Design Limited | Information & communication | 2019 |
| SANJAYMAHESH048 Ltd | Transport & logistics | 2026 |
| Sannity Consulting Limited | Hospitality | 2014 |
| Santiago Bars Limited | Hospitality | 2012 |
| SAO Consultants Ltd | Professional & scientific | 2024 |
| Saol Investments Ltd | Real estate | 2023 |
| Sapsford Consulting Engineers Ltd. | Professional & scientific | 2018 |
| SAR Overseas Ltd | Wholesale & retail | 2019 |
| Sarah Brazer (QP) Ltd. | Professional & scientific | 2015 |
| Sarah Edmonds Illustration Limited | Arts & recreation | 2021 |
| Sarah Ellis Consultancy Ltd | Professional & scientific | 2026 |
| Sarah Peckham Mortgages Limited | Financial services | 2018 |
| Sarah Peckham Properties Limited | Real estate | 2021 |