| SJ Marketing Solutions Ltd | Professional & scientific | 2024 |
| SJ Trades Ltd | Wholesale & retail | 2025 |
| SJ Trin Services Ltd | Other services | 2022 |
| SJ Walker & Co (Properties) Ltd | Extraterritorial | 2008 |
| SJG Interim & Consultancy Services Ltd | Health & social care | 2021 |
| SJS Saftey Solutions Limited | Professional & scientific | 2023 |
| SK Technology Consulting Ltd | Information & communication | 2026 |
| Sk!Ndr Limited | Health & social care | 2015 |
| Skadi Investment Management Ltd | Financial services | 2017 |
| Skillsmindset Ltd | Professional & scientific | 2007 |
| Skin Boutique Aesthetics Ltd | Health & social care | 2025 |
| Skin Sense Aesthetics Limited | Other services | 2020 |
| Skin Sense GP Clinic Limited | Health & social care | 2015 |
| Skindecision Tattoo Limited | Other services | 2007 |
| Sky View Cleaning Ltd | Administrative & support | 2019 |
| Skyreach Capital Ltd | Financial services | 2025 |
| SLB IT Solutions Limited | Information & communication | 2012 |
| Sldb Ltd | Manufacturing | 2021 |
| Slgk Solutions Ltd | Real estate | 2021 |
| SLH TAV Ltd | Hospitality | 2022 |
| Slsearch Ltd | Information & communication | 2022 |
| SLW Financial Planning Ltd | Professional & scientific | 2021 |
| Smac Plumbing and Heating Limited | Wholesale & retail | 2002 |
| Smart Freight Solutions Ltd | Transport & logistics | 2010 |
| Smart Insulated Renders Limited | Construction | 2020 |
| Smart Property Location Ltd | Real estate | 2017 |
| Smartcurriculum Ltd | Professional & scientific | 2010 |
| Smarter Building Solutions Limited | Information & communication | 2020 |
| Smarter Installations Ltd | Construction | 2022 |
| SMC Dog Training Ltd | Other services | 2025 |
| Smile Self Storage Limited | Transport & logistics | 2024 |
| Smith & Devil Ltd | Information & communication | 2021 |
| Smiths Scaffolding Solutions Ltd | Construction | 2021 |
| SMK HR Consultancy Ltd | Professional & scientific | 2026 |
| Smokeforge Terrain Limited | Manufacturing | 2026 |
| SO Forth Ltd | Health & social care | 2014 |
| Sobella Ltd | Hospitality | 2019 |
| Social Origin Limited | Professional & scientific | 2020 |
| Social Vibe CRM Limited | Administrative & support | 2025 |
| Socialife Management Ltd | Information & communication | 2024 |
| Sockgoal Ltd | Manufacturing | 2024 |
| Soft Play BUS Essex Ltd | Arts & recreation | 2023 |
| Soft Technologies Limited | Information & communication | 1996 |
| Solace Garden Rooms Limited | Construction | 2020 |
| Solby Wood Management (Hadleigh) Limited | Households | 2022 |
| Sollers Consulting Information Technology Limited | Information & communication | 2023 |
| Solophoenix Ltd | Health & social care | 2025 |
| Solvx Strategic Solutions Ltd | Professional & scientific | 2026 |
| Sonsaile Developments Ltd | Information & communication | 2019 |
| Sophanted Ltd | Education | 2023 |
| Sophisti-Cuts Canvey Island Ltd | Other services | 2015 |
| Sorrells Wine Racks Limited | Manufacturing | 2000 |
| SOS Construction (Design & Build) Limited | Administrative & support | 2016 |
| SOS Fencing Ltd | Administrative & support | 2021 |
| SOS Gardens & Landscapes Ltd | Administrative & support | 2016 |
| SOS Securities TM Limited | Administrative & support | 2017 |
| Sossco Ltd | Manufacturing | 2025 |
| Sostvradio Limited | Extraterritorial | 2015 |
| Soundtrack (Audio-Visual) Limited | Wholesale & retail | 1968 |
| Sourcepac Ltd | Wholesale & retail | 2017 |
| South Benfleet Primary School | Education | 2011 |
| South East Contract Cleaning Limited | Administrative & support | 2012 |
| South East Essex Academy Trust | Education | 2011 |
| South Eastern Road & Groundworks Limited | Wholesale & retail | 1999 |
| South Eastern Road Tankers Limited | Manufacturing | 1982 |
| South Essex Academy Trust | Education | 2011 |
| Southend 7 Limited | Construction | 2024 |
| Southend Furniture Warehouse Ltd | Wholesale & retail | 2022 |
| Southend House Removals Ltd | Transport & logistics | 2021 |
| Southend United Football Club Limited(The) | Arts & recreation | 1906 |
| Southern Accountancy Limited | Professional & scientific | 1997 |
| Southern Cross Property Services Ltd | Construction | 2022 |
| Southview Surveyors Limited | Professional & scientific | 2020 |
| Southview Surveyors LLP | | 2011 |
| Sovereign Court (Eastbourne) Management Company Limited | Real estate | 2003 |
| Sovereign Property Estate Limited | Real estate | 2018 |
| Spa Life Events Ltd | Other services | 2014 |
| Space YEW Ltd | Professional & scientific | 2022 |
| Spdf UK Ltd | Construction | 2016 |
| Special F X Double Glazing Limited | Construction | 1995 |
| Specialized Welding & Fabrication Ltd | Manufacturing | 2009 |
| Spectrum Groundworks Limited | Construction | 2010 |
| Spectrum Tower (Ilford) RTM Company Ltd | Households | 2018 |
| Speybrig Bodies Limited | | 1977 |
| Spink Consulting & Property Ltd | Professional & scientific | 2014 |
| Spinning Disc Records Limited | Information & communication | 2009 |
| Splendid Furniture Company Limited | Wholesale & retail | 2012 |
| SPM Civil Engineering Ltd | Professional & scientific | 2020 |
| Sport Investments Ltd | Arts & recreation | 2017 |
| Sportamins Ltd | Wholesale & retail | 2024 |
| Sporting Events (UK) Limited | Arts & recreation | 2005 |
| Sporting Events Limited | Arts & recreation | 2000 |
| Sports Turf Limited | Administrative & support | 2022 |
| Spotless Window Cleaning Essex Limited | Other services | 2013 |
| Springfield Consulting Ltd | Professional & scientific | 2024 |
| SQR Carpentry & Construction Ltd | Construction | 2020 |
| SQS Benfleet Ltd | Professional & scientific | 2024 |
| Squeaky Services Limited | Administrative & support | 2024 |
| SR Conversions Ltd | Construction | 2022 |
| SRT Commercial Repairs Limited | Wholesale & retail | 2026 |