| Space Apartments Harwich Ltd | Real estate | 2021 |
| Space Apartments Ltd | Real estate | 2025 |
| Space Film & TV Studios Limited | Information & communication | 2024 |
| Space for Waste Ltd | Manufacturing | 2025 |
| Spanfix Limited | Construction | 2003 |
| Sparhawk MEP Ltd | Construction | 2023 |
| Spark Sync Shift Ltd | Education | 2026 |
| Spark Theatrical Entertainment Limited | Arts & recreation | 2016 |
| Sparkle Magic Pro Cleaning Ltd | Administrative & support | 2025 |
| Sparkles Home Interiors Limited | Wholesale & retail | 2018 |
| Sparkling & Bright Cleaning Ltd | Administrative & support | 2019 |
| Sparkling Blue Limited | Extraterritorial | 2015 |
| Sparks Electrical Solutions (Essex) Limited | Construction | 2016 |
| SPARKY24 Limited | Construction | 2025 |
| Sparrows Holdings Limited | Real estate | 2020 |
| Sparrows Limited | Education | 2007 |
| Spartan Security Soloutions Ltd | Administrative & support | 2025 |
| SPC Electrical Solutions Ltd | Construction | 2018 |
| Spearhead Healthcare Plus Ltd | Health & social care | 2023 |
| Specialised Fixings (East Anglia) Limited | Construction | 2021 |
| Specialist Coating & Lining Services Ltd | Administrative & support | 2025 |
| Specialist Inventory Services Limited | Administrative & support | 2006 |
| Specnota Ltd | Information & communication | 2020 |
| Spectrum Advisory Ltd | Professional & scientific | 2025 |
| Spectrum Glazing Limited | Construction | 2017 |
| Spectrum Occupational Therapy Limited | Health & social care | 2016 |
| Spectrum Scaffolding Ltd | Construction | 2026 |
| Spectrum Screen Events Ltd | Hospitality | 2019 |
| Speed-Removals International Ltd | Water & waste | 2016 |
| Speedbird Energy Ltd | Professional & scientific | 2024 |
| Speedlettings Limited | Real estate | 2007 |
| Spence Elec Limited | Construction | 2016 |
| Spencer Court (South Woodham Ferrers) Management Company Limited | Households | 1984 |
| SPH Business Solutions Limited | Professional & scientific | 2006 |
| SPH Landscapes Limited | Administrative & support | 2002 |
| Sphere Consolidated Holdings U.K. Limited | Financial services | 1982 |
| Sphere Technical Services Ltd | Wholesale & retail | 2016 |
| Spice Garden of India Limited | Wholesale & retail | 2023 |
| Spice of India UK Ltd | Hospitality | 2017 |
| Spice Rack Ltd | Hospitality | 2022 |
| Spicerhaart Corporate Sales Limited | Administrative & support | 2008 |
| Spicerhaart Estate Agents Limited | Administrative & support | 2002 |
| Spicerhaart Financial Services Limited | Professional & scientific | 2006 |
| Spicerhaart Group Limited | Administrative & support | 2000 |
| Spicerhaart Group Services Limited | Administrative & support | 2008 |
| Spicerhaart Land & New Homes Limited | Administrative & support | 2010 |
| Spicerhaart Professional Services Limited | Administrative & support | 2001 |
| Spicerhaart Property Services Limited | Administrative & support | 2008 |
| Spicerhaart Residential Lettings Limited | Real estate | 2004 |
| Spidy-Lodge Limited | Administrative & support | 2009 |
| Spindles Road Sweeping Ltd | Administrative & support | 2005 |
| Spinlear Ltd | Information & communication | 2021 |
| Spinon Ltd | Information & communication | 2012 |
| Spirals Brightlingsea Ltd | Wholesale & retail | 2011 |
| Spire Media Limited | Professional & scientific | 2009 |
| Spirit of the Moon Limited | Wholesale & retail | 2026 |
| Spirit Print Ltd | Manufacturing | 2010 |
| Spirited Slice Pizza Limited | Hospitality | 2025 |
| Spiritual Balance Ltd | Other services | 2018 |
| Spko Ltd | Wholesale & retail | 2013 |
| SPM Security Ltd | Administrative & support | 2022 |
| Spontaneous Hub Limited | Administrative & support | 2025 |
| Spontino Ltd | Hospitality | 2025 |
| Spookinory Events Ltd | Arts & recreation | 2022 |
| Spore and Stem Ltd | Agriculture & fishing | 2026 |
| Sport and Health Unite Ltd | Education | 2010 |
| Sport Invest International Limited | Information & communication | 2006 |
| Sport World Limited | Administrative & support | 2005 |
| Sporting Horses Ltd | Wholesale & retail | 2011 |
| Sportrition Limited | Wholesale & retail | 2024 |
| Sports & Deep Tissue Massage Ltd | Other services | 2024 |
| Sports Entertainment Marketing Media Limited | Administrative & support | 2016 |
| Sports Ground Irrigation Limited | Extraterritorial | 1997 |
| Sports Injury IQ Ltd | Health & social care | 2026 |
| Sports Medicine United Ltd | Health & social care | 2021 |
| Sports Supplements Ltd | Wholesale & retail | 2005 |
| Sports Way Management Ltd | Wholesale & retail | 2016 |
| Sportsafe UK Ltd | Administrative & support | 1997 |
| Spotless Services (South East) Limited | Administrative & support | 2016 |
| Spring (Cultivated) Limited | Administrative & support | 2005 |
| Spring Business Services Limited | Professional & scientific | 2019 |
| Spring GM Ltd | Administrative & support | 2018 |
| Spring Rise Physio Clinic Limited | Health & social care | 2017 |
| Spring Success Care Homes Limited | Health & social care | 2017 |
| Spring Success Home Care Limited | Health & social care | 2023 |
| Spring Valley Properties Limited | Real estate | 1959 |
| Springfield Place Property Management Limited | Real estate | 2012 |
| Springwood Close Management Company Limited | Households | 2021 |
| Spritzmonkey Group Limited | Financial services | 2023 |
| Spry & Sons Property Limited | Real estate | 2026 |
| Spry IT Solutions Ltd | Information & communication | 2015 |
| SPT Plastering Contractors Limited | Construction | 2014 |
| Squadserve Limited | Administrative & support | 2015 |
| Square Mile Finance Limited | Financial services | 2012 |
| Square One Building Safety Ltd | Professional & scientific | 2026 |
| Square One IP Vault Ltd | Professional & scientific | 2026 |
| Squarity Ltd | Arts & recreation | 2012 |
| Squirrels Hall Fruit Farm | Agriculture & fishing | 1968 |
| Squirrels Storage Ltd | Transport & logistics | 2026 |
| SR Build Solutions Limited | Construction | 2015 |