| Song Cake Entertainment Ltd | Information & communication | 2025 |
| Sonico Barbers Ltd | Other services | 2022 |
| Sonjay Prabhakar Limited | Manufacturing | 2022 |
| Sopers & SON Ltd | Construction | 2023 |
| SOR Housing Ltd | Real estate | 2020 |
| SOS Combatives CIC | Education | 2025 |
| SOS Hair Ltd | Other services | 2019 |
| Sost Limited | Other services | 2019 |
| South Auto Body Shop Ltd | Other services | 2021 |
| South East Bars & Pubs Ltd | Hospitality | 2018 |
| South East Shavings Limited | Manufacturing | 2020 |
| South Essex Community School Ltd | Education | 2012 |
| South Essex Facilities Management Limited | Administrative & support | 2023 |
| South Essex Fasteners Limited | Wholesale & retail | 1974 |
| South Essex Leasing Limited | Administrative & support | 1996 |
| South Essex Pallets Limited | Transport & logistics | 2019 |
| South Essex Streetwear Ltd | Wholesale & retail | 2025 |
| South London Ground Rents Limited | Real estate | 2009 |
| South London Holding Company Limited | Manufacturing | 2017 |
| South Point RTM Company Limited | Real estate | 2011 |
| South Records Ltd | Wholesale & retail | 2013 |
| South Street Coffee Ltd | Hospitality | 2024 |
| Southchurch Commercial Property Limited | Real estate | 2024 |
| Southchurch Discount Sales Limited | Construction | 1977 |
| Southchurch Property Limited | Real estate | 2024 |
| Southend Airport Chauffeur Limited | Transport & logistics | 2024 |
| Southend Airport Travel Limited | Transport & logistics | 2020 |
| Southend AM 2 PM Ltd | Wholesale & retail | 2012 |
| Southend Auto Sales Limited | Wholesale & retail | 2017 |
| Southend Best HCW Ltd | Administrative & support | 2017 |
| Southend Car Hub Ltd | Wholesale & retail | 2026 |
| Southend Car Wash Ltd | Wholesale & retail | 2026 |
| Southend Care Ltd | Health & social care | 2016 |
| Southend City Radio CIC | Information & communication | 2025 |
| Southend Cleaning.Com Ltd | Administrative & support | 2025 |
| Southend Construction Trade Limited | Construction | 2021 |
| Southend Drawing Club Ltd | Arts & recreation | 2024 |
| Southend Drink and Sweet Limited | Wholesale & retail | 2023 |
| Southend East Community Academy Trust | Education | 2011 |
| Southend East Limited | Construction | 2010 |
| Southend Electrical Services Ltd | Construction | 2016 |
| Southend Engineering Services Ltd | Professional & scientific | 2007 |
| Southend Football Supporters'Social Club Limited | Hospitality | 1937 |
| Southend Heating & Plumbing Limited | Wholesale & retail | 2014 |
| Southend High School for Boys Academy Trust | Education | 2011 |
| Southend High School for Girls Academy Trust | Education | 2011 |
| Southend Homes Limited | Real estate | 2025 |
| Southend Housing Ltd | Professional & scientific | 2016 |
| Southend Lawn Tennis Club Trustees Limited | Arts & recreation | 2018 |
| Southend Meenatshe Suntharasar Kovil | Other services | 2017 |
| Southend Motor Services Limited | Wholesale & retail | 2025 |
| Southend Nail and Beauty School Ltd | Education | 2013 |
| Southend Pier Museum Foundation Trust Limited | Arts & recreation | 1989 |
| Southend Plumber Limited | Construction | 2016 |
| Southend Steels Limited | Wholesale & retail | 2021 |
| Southend Street Gym Limited | Arts & recreation | 2017 |
| Southend Tamil School CIC | Education | 2021 |
| Southend Ultrasound Services Limited | Health & social care | 2019 |
| Southend-On-Sea Forum Management Ltd | Real estate | 2011 |
| Southend-On-Sea Freemasons' (Trustees) Limited | Extraterritorial | 2010 |
| Southendphone Limited | Wholesale & retail | 2025 |
| Southern Dreamscapes Ltd | Professional & scientific | 2024 |
| Southover Construction Ltd | Construction | 2014 |
| Southpoint Sutton Road Management Company Limited | Households | 2016 |
| Sovereignty Coins Limited | Wholesale & retail | 2017 |
| SP Property Development Ltd | Real estate | 2025 |
| SP Recruitment (London) Limited | Administrative & support | 2019 |
| SP8 Installations Ltd | Construction | 2024 |
| Sparkbridge Limited | Construction | 1988 |
| Sparkle UK Limited | Manufacturing | 2000 |
| Sparkling World Ltd | Health & social care | 2023 |
| Special FX Holdings Ltd | Financial services | 2026 |
| Specialised Cleaning Solutions Limited | Administrative & support | 2015 |
| Specialised Rentals Limited | Administrative & support | 2025 |
| Specialist Support UK Limited | Professional & scientific | 2016 |
| Spectre Hill (Cheltenham) Management Company Limited | Households | 2022 |
| Spectre Leisure Ltd | Hospitality | 2021 |
| Speedygo Couriers Ltd | Transport & logistics | 2025 |
| Speights Court Limited | Households | 2004 |
| Spice House Southend Limited | Hospitality | 2024 |
| Spice HUT KNA Limited | Hospitality | 2026 |
| Spice HUT Southend-On -Sea Ltd | Hospitality | 2026 |
| Spice Villa & Grill Ltd | Hospitality | 2025 |
| Spinningfields Wealth Partners Limited | Financial services | 2018 |
| Spinrose Limited | Professional & scientific | 2022 |
| Spire Vista Ltd | Administrative & support | 2012 |
| SPIRO2 Limited | Professional & scientific | 2025 |
| Splashytoes Ltd | Education | 2025 |
| SPM Associates Limited | Professional & scientific | 2014 |
| Sponsorwise Ltd | Extraterritorial | 2023 |
| Sporting People Limited | Arts & recreation | 2018 |
| Sports, Rock & Roll & Haircuts Limited | Other services | 1998 |
| Sportwagen Limited | Other services | 2001 |
| Sposworld Limited | Wholesale & retail | 2026 |
| Spotlight Human Resources Limited | Professional & scientific | 2014 |
| Springhouse Management Limited | Households | 1997 |
| Spud YA Ltd | Hospitality | 2025 |
| SPV Homes (Essex) Ltd | Real estate | 2020 |
| SPV Reporting Limited | Health & social care | 2010 |
| SQ1 Decorating Ltd | Construction | 2025 |