| Ryan Tax and Accountancy Limited | Professional & scientific | 2025 |
| S & B MEP Systems Limited | Construction | 2016 |
| S. Scanlon Limited | Professional & scientific | 2020 |
| S.O.L.D Limited | Real estate | 2021 |
| Sacred OIL Ltd | Manufacturing | 2018 |
| Sacred Space Cleaning Ltd | Administrative & support | 2026 |
| Sadler Carpentry and Construction Ltd | Construction | 2025 |
| SAH Real Estate Group Ltd | Real estate | 2022 |
| Sangson Limited | Wholesale & retail | 1975 |
| Sarjan Works Limited | Information & communication | 2024 |
| Sawasdee Property Ltd | Real estate | 2024 |
| SBD Electrical Limited | Construction | 2025 |
| SCD Consulting Ltd | Information & communication | 2025 |
| Schön Design Technologies Ltd | Manufacturing | 2021 |
| SCS Contract Management Limited | Construction | 2007 |
| SDK Global Enterprises Limited | Financial services | 2024 |
| Sea Road Management Ltd | Real estate | 2023 |
| Sebastian Rail Limited | Construction | 2019 |
| Seetec Employee Ownership Trustee Limited | Administrative & support | 2019 |
| Seetec Justice Limited | Public administration | 2019 |
| Seetec Outsource Training and Skills Limited | Education | 2019 |
| Seetec Pluss Limited | Education | 2019 |
| Select Remoulds Ltd | Manufacturing | 1997 |
| Select Tyres Ltd | Wholesale & retail | 2021 |
| Select Woodfinishing Services Ltd | Manufacturing | 2012 |
| Sellwood Electrical Services Limited | Energy | 2024 |
| Semas Systems Ltd | Professional & scientific | 2023 |
| Sense Sensory Ltd | Education | 2016 |
| SET the Tone Remote Sales Ltd | Education | 2026 |
| Setonia Tiling Ltd | Manufacturing | 2025 |
| SG Scaffolding Services Limited | Construction | 2025 |
| SG Sons Limited | Real estate | 2022 |
| SG Sons Retail Ltd | Wholesale & retail | 2022 |
| Shadow Events Ltd | Arts & recreation | 2020 |
| Shangri LA Cattery Ltd | Agriculture & fishing | 2016 |
| Shaw Heating Ltd | Construction | 2022 |
| Shields Mechanical Services Ltd | Construction | 2026 |
| Shores Property Ltd | Construction | 2019 |
| Sid's Vehicle Solutions Limited | Wholesale & retail | 2014 |
| SJL Premier Solutions Limited | Professional & scientific | 2019 |
| Skyblu IQ Ltd | Professional & scientific | 2021 |
| Sledline Ltd | Wholesale & retail | 2025 |
| Small Family Business Ltd | Professional & scientific | 2025 |
| Smart Cert Pro Limited | Information & communication | 2025 |
| Smartblox Limited | Extraterritorial | 2021 |
| Social Agenda Limited | Real estate | 2013 |
| Soft Soles Essex Limited | Health & social care | 2017 |
| Soft Soles Ltd. | Health & social care | 2017 |
| SOMETHING2SING Limited | Administrative & support | 2009 |
| Soper Building Solutions Limited | Construction | 2012 |
| Sound Motorsport Ltd | Wholesale & retail | 2025 |
| South Essex Construction Limited | Construction | 2020 |
| South Essex Media Productions Ltd | Information & communication | 2020 |
| South Woodham Garage Ltd | Wholesale & retail | 2005 |
| Southend Elite Sports Academy Limited | Arts & recreation | 2021 |
| Specialist Installation Services Ltd | Construction | 2024 |
| Spencer Roofing & Lining Ltd | Construction | 2014 |
| Spencers House Limited | Professional & scientific | 2008 |
| Spirit ASH Studio Ltd | Wholesale & retail | 2023 |
| SPM Resonance Ltd | Other services | 2023 |
| SR Retail Store Ltd | Wholesale & retail | 2024 |
| SRS Medical Limited | Health & social care | 2015 |
| Standout Limited | Wholesale & retail | 2005 |
| Starlight Stem Limited | Education | 2018 |
| Startup Boost Ltd | Other services | 2021 |
| Stephensons Cleaning Limited | Other services | 2011 |
| Stormwhip Limited | | 1967 |
| Straight Outta Japan Ltd | Wholesale & retail | 2023 |
| Strivana Limited | Health & social care | 2025 |
| Stryx Club Ltd | Wholesale & retail | 2025 |
| Stylehubuk Ltd | Wholesale & retail | 2022 |
| Sullivan Construction Refurbishment Ltd | Construction | 2005 |
| Superior Building Solutions Ltd | Construction | 2025 |
| Supreeth Limited | Health & social care | 2015 |
| Symmetry Studios Hockley Ltd | Arts & recreation | 2024 |
| T & T Gutter Services Ltd | Administrative & support | 2023 |
| T&C's Property Ltd | Real estate | 2019 |
| Take Five Aromatherapy Limited | Wholesale & retail | 2019 |
| Targeted Health Care Ltd | Health & social care | 2022 |
| Taurus Transportation Ltd | Administrative & support | 2021 |
| Taxi for Nick Limited | Professional & scientific | 2017 |
| Taylorchiro Ltd | Health & social care | 2025 |
| Taylorcrest Ltd | Wholesale & retail | 2022 |
| TDM1 Limited | Construction | 2021 |
| Tearabyte Software Solutions Ltd | Information & communication | 2024 |
| Teardrop Hydroponics Ltd | Agriculture & fishing | 2024 |
| Teare Group Ltd | Financial services | 2024 |
| Techline Group Ltd | Transport & logistics | 2026 |
| TEK Pools Ltd | Construction | 2020 |
| Terminus Homes Consultancy Limited | Professional & scientific | 2018 |
| TEX 24 Consultants Ltd | Construction | 2025 |
| TG Properties (Investments) Ltd | Real estate | 2021 |
| TG Properties Limited | Real estate | 2017 |
| Tgas Consulting Ltd | Arts & recreation | 2020 |
| TGW Design Limited | Information & communication | 2018 |
| Thackray & Holder Limited | Health & social care | 2013 |
| Thamesside IT Services Ltd | Information & communication | 2014 |
| THE Alcohol Free Co Ltd | Hospitality | 2019 |
| THE Aldermans Freehold Company Limited | Households | 2025 |
| THE Astors Management Company Limited | Real estate | 2014 |