| SMS Legal Consultants Ltd | Professional & scientific | 2017 |
| Smudge Limited | Real estate | 2025 |
| Snag List Pro Ltd | Construction | 2020 |
| SNI Consultancy Ltd | Construction | 2013 |
| SNK Marketing Limited | Professional & scientific | 2016 |
| SO BUR Clothing Retail Ltd | Wholesale & retail | 2025 |
| Sohl Services Limited | Real estate | 2016 |
| Sohpal Consultancy Limited | Information & communication | 2011 |
| Solaris Holdings Ltd | Real estate | 2024 |
| Solaris Life Therapy Limited | Administrative & support | 2010 |
| Solefield School Educational Trust Limited | Education | 1985 |
| Solent Development Management Limited | Construction | 2017 |
| Solex Renewable Energies Ltd | Construction | 2023 |
| Soley Organics UK Limited | Wholesale & retail | 2017 |
| Solid Advisory Ltd | Professional & scientific | 2024 |
| Solo ACT Limited | Other services | 2015 |
| Sommer Consulting Limited | Professional & scientific | 2015 |
| Sommer Properties Ltd | Real estate | 2021 |
| Sommi Pizza Ltd | Hospitality | 2020 |
| Sommi's Wood-Fired Pizza Company Ltd | Hospitality | 2020 |
| Sonate Fire Solutions Limited | Public administration | 2026 |
| Sonda Technologies Ltd | Professional & scientific | 2024 |
| Sonderastudios Ltd | Information & communication | 2026 |
| Songarc Ltd | Information & communication | 2026 |
| Sonic Limited | Construction | 1998 |
| Sonic Syndicate Ltd | Wholesale & retail | 2015 |
| Soopanda Ltd | Real estate | 2022 |
| Sophie Lorraine Permanent Makeup Ltd | Other services | 2021 |
| Sophie Stuff Ltd | Wholesale & retail | 2025 |
| Sophisticated Construction Ltd | Construction | 2019 |
| Sopro Holdings Limited | Information & communication | 2016 |
| Sorry Limited | Professional & scientific | 2021 |
| Soteria Retail Ltd | Wholesale & retail | 2026 |
| Soterius (Holdings) Limited | Financial services | 2017 |
| Soulflow Group Limited | Construction | 2025 |
| Soulmatefilm Limited | Information & communication | 2012 |
| Sound Affects Limited | Information & communication | 1984 |
| Sound Asleep Asmr Limited | Information & communication | 2024 |
| Soundbalance Ltd | Information & communication | 2015 |
| Sourcenergy Ltd | Construction | 2017 |
| South East Autoclave Limited | Manufacturing | 2014 |
| South East Business Centres Limited | Real estate | 1995 |
| South East Construction Consortium LLP | | 2010 |
| South East Groundworks Limited | Construction | 2016 |
| South East Hvac Design & Installations Ltd | Construction | 2026 |
| South East Rescue Ltd | Transport & logistics | 2021 |
| South Grove Investments Ltd | Real estate | 2023 |
| South Grove Ventures Ltd | Real estate | 2023 |
| South Ockendon Investments Limited | Real estate | 1965 |
| South of the River Limited | Wholesale & retail | 2000 |
| Southampton Way Limited | Construction | 2020 |
| Southeast Irrigation Limited | Professional & scientific | 2026 |
| Southern Alps Limited | Manufacturing | 2001 |
| Southfields Mews Limited | Households | 2022 |
| Southside Fabrication Ltd | Manufacturing | 2026 |
| Sovereign (Financial Management) Limited | Information & communication | 1986 |
| Sovereign (Financial Services) Limited | Financial services | 1979 |
| SP Finserv Limited | Real estate | 2008 |
| SP Mitchell Ltd | Professional & scientific | 2021 |
| Spa Caffe Limited | Hospitality | 2012 |
| Space Accountancy Limited | Real estate | 2001 |
| Spaceman London Limited | Construction | 2016 |
| Spagrove Limited | Construction | 1981 |
| Spark Business Networking Limited | Administrative & support | 2023 |
| Sparkle Carpet Cleaner & Upholstery Cleaner Sevenoaks Kent Ltd | Administrative & support | 2024 |
| Spars Holdings Ltd | Real estate | 2016 |
| Spatial Dimensions Limited | Professional & scientific | 2012 |
| Spatial Homes Limited | Real estate | 2020 |
| Specialist Global Marketing Ltd | Wholesale & retail | 2016 |
| Specialist Kitchen Fitters Limited | Construction | 2015 |
| Spectrumitech Limited | Information & communication | 2002 |
| Spencer & Stroud Properties Limited | Real estate | 2025 |
| SPH Accessories Ltd | Wholesale & retail | 2017 |
| SPH Cars Ltd | Wholesale & retail | 2018 |
| Spic and Span London Ltd | Administrative & support | 2026 |
| Spiers Productions Ltd | Professional & scientific | 2014 |
| Spilka Ltd | Administrative & support | 2025 |
| Spinks PR and Communications Ltd | Other services | 2017 |
| Spinnaker Consulting Limited | Administrative & support | 2023 |
| Spiritfilled Ltd | Wholesale & retail | 2016 |
| Spiritual Planet Limited | Wholesale & retail | 2005 |
| Spirrit Limited | Real estate | 2000 |
| Sports Posters UK Limited | Wholesale & retail | 2025 |
| Sportsplaymotion Ltd | Education | 2019 |
| Sportsrisks Ltd | Extraterritorial | 1999 |
| Spot the HOG Limited | Hospitality | 2011 |
| Spot Vehicle Hire Limited | Administrative & support | 2019 |
| Spotlight Diverse Marketing Kent Ltd | Other services | 2012 |
| Spray Resins Limited | Manufacturing | 2019 |
| Spread Grazing Events Ltd | Hospitality | 2026 |
| Springfield Projects Limited | Construction | 2002 |
| Springfields Consulting Limited | Professional & scientific | 2019 |
| Springhill Estate (IOW) Ltd | Real estate | 2015 |
| Sprnt Advisory Limited | Information & communication | 2024 |
| Spurgeon Walker Ltd | Professional & scientific | 1975 |
| SPY Readers Limited | Education | 2022 |
| Spyder Performance Limited | Wholesale & retail | 2017 |
| Sqib Limited | Professional & scientific | 2013 |
| Square Golf Ltd | Wholesale & retail | 2026 |
| Squared Legal Limited | Administrative & support | 2018 |