| Softorque Limited | Information & communication | 1986 |
| Software Arts Limited | | 1987 |
| Soho Ekspres Limited | Information & communication | 2026 |
| Sojourn Projects Ltd | Arts & recreation | 2014 |
| Sokol Petriti T/A Tom's Kitchen Ltd | Hospitality | 2022 |
| Soledash Limited | | 1987 |
| Solento Limited | Real estate | 2019 |
| Solid Bond Productions Limited | Arts & recreation | 1986 |
| Solid Bond Properties Limited | Real estate | 2024 |
| Solid Foundations UK Limited | Wholesale & retail | 2008 |
| Solid Projects Limited | Professional & scientific | 2003 |
| Solomon ADL Limited | Professional & scientific | 2013 |
| Somers Centre Limited | Professional & scientific | 1978 |
| Songs in LEW Limited | Arts & recreation | 1999 |
| Sons of Pioneers Limited | Information & communication | 1978 |
| Sony Europe Limited | Professional & scientific | 2024 |
| Sood Properties Limited | Real estate | 2006 |
| Soothe With Saintsville CIC | Education | 2026 |
| Sophocles Bakery Limited | Manufacturing | 2003 |
| Sorc Limited | Transport & logistics | 2022 |
| SOS Equestrian Limited | Agriculture & fishing | 2018 |
| Sotily Trading Company Limited | Health & social care | 1993 |
| Sound Associates Limited | Wholesale & retail | 1960 |
| South and South East in Bloom | Professional & scientific | 2002 |
| South Atlantis Investments Limited | Professional & scientific | 1909 |
| South Central Maintenance Services Limited | Construction | 2007 |
| South Coast Plumbers Ltd | Construction | 2022 |
| South East Academy of Golf Limited | Arts & recreation | 1990 |
| South East Cancer Help Centre Limited | Health & social care | 1992 |
| South East London Entertainment Company Ltd | Information & communication | 1994 |
| South Eastern Supplies Limited | Wholesale & retail | 1995 |
| South London Auto Paints Limited | Wholesale & retail | 1995 |
| South London Investment Co. Limited | Real estate | 1958 |
| South Thames Consultancy and Training Limited | Health & social care | 1993 |
| Southern CC Limited | Health & social care | 1986 |
| Southern Superjet Limited | Administrative & support | 2002 |
| Southern Transformer Products Limited | Professional & scientific | 1973 |
| Southland Kitchens Limited | | 1985 |
| Southpark Holding Ltd | Real estate | 2015 |
| Southview Design Limited | Manufacturing | 2006 |
| Southwest London Tamil Kalvikoodam | Education | 2007 |
| Southwinds Construction Specialists UK Ltd | Real estate | 2026 |
| Sovereign Wheels Ltd | Manufacturing | 2016 |
| SP Pharm Limited | Health & social care | 2004 |
| SP Properties Group Ltd | Real estate | 2023 |
| Space Truck Rental Ltd | Administrative & support | 2016 |
| Spadek Ltd | Professional & scientific | 2002 |
| Spark Software Limited | Information & communication | 2007 |
| Sparkes Welding Ltd. | Manufacturing | 1996 |
| Sparkling Perry Limited | Professional & scientific | 2003 |
| Speciality Crop Consulting Ltd | Agriculture & fishing | 2019 |
| Spectre Consultancy Ltd. | Professional & scientific | 1997 |
| Speed 8941 Limited | Wholesale & retail | 2001 |
| Speedline Computer Services Limited | Professional & scientific | 1986 |
| Speedorigami Ltd | Information & communication | 2007 |
| Speedtwin Developments Limited | Manufacturing | 1993 |
| Spellings Business Services Limited | Information & communication | 1995 |
| Spicer Marsh Limited | Real estate | 1976 |
| Spicyfoods Limited | Wholesale & retail | 1974 |
| Spike Media Limited | Information & communication | 2004 |
| Spinnaker Management Resources Ltd. | Professional & scientific | 2007 |
| SPJ Autos Limited | Wholesale & retail | 2005 |
| Splendid Houses Limited | Hospitality | 2008 |
| Splinks Limited | Information & communication | 2004 |
| Split Level Air Conditioning Limited | Energy | 2009 |
| Sporting Affair Limited | Administrative & support | 1998 |
| Sports Car Products Limited | Extraterritorial | 2007 |
| Spotless Facility Services Ltd | Administrative & support | 2005 |
| Spotlight Properties (UK) Limited | Information & communication | 2005 |
| SPP Technical Designs Limited | Professional & scientific | 2003 |
| SPR Engineering Limited | Construction | 2006 |
| SPR Investments Ltd | Real estate | 2006 |
| Springboard ASA Limited | Information & communication | 2002 |
| Springfield Road Residents Association Limited | Households | 1974 |
| Springs MCR Devco Ltd | Construction | 2025 |
| Springs MCR Finco Ltd | Financial services | 2025 |
| Springs MCR Holdco Ltd | Financial services | 2025 |
| Springs MCR Midco 1 Ltd | Financial services | 2025 |
| Springs MCR Midco 2 Ltd | Financial services | 2025 |
| Springs MCR Midco 3 Ltd | Financial services | 2025 |
| Springs MCR Opco Ltd | Professional & scientific | 2025 |
| Springshaw Developments Ltd. | Information & communication | 1986 |
| Sprite Projects Limited | Transport & logistics | 1997 |
| Spyrax (UK) Limited | Professional & scientific | 1991 |
| Square PEG International Limited | Professional & scientific | 2003 |
| Square Root Holdings Limited | Professional & scientific | 2000 |
| Square Root Limited | Administrative & support | 1995 |
| Squires Court Management Company Limited | Households | 1997 |
| SR Art Limited | Professional & scientific | 2004 |
| SR Gardening Services Ltd | Administrative & support | 2003 |
| SR Surbiton Ltd | Hospitality | 2018 |
| Srai Homes Ltd | Real estate | 2019 |
| Srasha Homes Limited | Real estate | 2025 |
| Sree IT Consulting Ltd | Information & communication | 2015 |
| Srgs Holdings Ltd | Transport & logistics | 2024 |
| SRI Lankan Tamil Shop Limited | Wholesale & retail | 2007 |
| Sril Catering Co. Ltd | Hospitality | 2019 |
| SS Mitcham Properties Ltd | Real estate | 2022 |
| SSA Accountants Ltd | Professional & scientific | 2000 |
| SSA Riverside Ltd | Real estate | 2025 |