| Smoke Safe Limited | Construction | 2023 |
| SMU Management Limited | Extraterritorial | 2018 |
| Snack Cure Ltd | Hospitality | 2020 |
| Snowflake Gelato Group Limited | Other services | 2012 |
| Snowflake Gelato Ltd | Other services | 2011 |
| Snowflake Gelato Services Limited | Other services | 2017 |
| Snowflake Gelato Wholesale Limited | Other services | 2017 |
| Snowflake Luxury Gelato Limited | Other services | 2017 |
| Sobranie Limited | Real estate | 2020 |
| Soc!Ety Dance Academy Ltd | Education | 2018 |
| Societal AI Ltd | Professional & scientific | 2025 |
| Sofia Construction Ltd | Construction | 2025 |
| Sofiia Strakhova Iconography Ltd | Construction | 2026 |
| Software Quality Assurance (Management) Limited | Professional & scientific | 1996 |
| Software Testing Knowledge Group Limited | Other services | 2002 |
| Software Testing Knowledge Ltd | Information & communication | 2005 |
| Soho Films Limited | Information & communication | 2023 |
| Soho Loop Development Limited | Construction | 2021 |
| Solajo Ltd | Real estate | 2020 |
| Solarent Property Management Ltd | Real estate | 2025 |
| Solis Solutions Ltd | Information & communication | 2014 |
| Solo Electronic Solutions Ltd | Manufacturing | 2015 |
| SOLUTION4 Ltd | Information & communication | 2010 |
| Solutions Legal Limited | Professional & scientific | 2022 |
| Somerhaze Limited | Administrative & support | 2011 |
| Somerton Road (Cricklewood) Flat Management Company Limited | Households | 2001 |
| Something About Media Limited | Administrative & support | 2004 |
| Something About Rocks Limited | Administrative & support | 2021 |
| Sonia Rose Fitness Ltd. | Health & social care | 2018 |
| Soper Estates Limited | Real estate | 2022 |
| Sophie Makes Gifts Limited | Manufacturing | 2020 |
| Sophocli Properties Ltd | Real estate | 2021 |
| Soso London Ltd. | Manufacturing | 2014 |
| Soul Candy Entertainment Ltd | Information & communication | 2017 |
| Soul Disclosure Limited | Extraterritorial | 2020 |
| Soul Serenity Studio Ltd | Health & social care | 2024 |
| Source Productions Ltd | Manufacturing | 2009 |
| South Birkbeck Road (Blocks a & B) Management Company Limited | Households | 1986 |
| Southfields Real Estate Ltd | Real estate | 2025 |
| Southwark Boat Hire Ltd | Arts & recreation | 2024 |
| Southwark Park Road Developments Limited | Real estate | 2014 |
| Sovereign Home Improvements Limited | Construction | 2012 |
| SP IT Services Ltd | Wholesale & retail | 2021 |
| SP Living Ltd | Real estate | 2019 |
| SP Property Partners Limited | Real estate | 2026 |
| Spagna Food Selection Ltd | Wholesale & retail | 2019 |
| Sparklers and Fireworks Ltd | Other services | 2015 |
| Speaker Collective Limited | Information & communication | 2025 |
| Special Gifts Limited | Wholesale & retail | 2025 |
| Specialised Cleaning Services Limited | Administrative & support | 2009 |
| Spectrum Consultancy Services Limited | Information & communication | 2017 |
| Speech Therapy Interactive Ltd | Health & social care | 2020 |
| Spektris Ltd | Professional & scientific | 2019 |
| Spencer & Arlington Limited | Health & social care | 2002 |
| Spencer Adams Digital Limited | Extraterritorial | 2023 |
| Spencer Curtis Estates Limited | Real estate | 2000 |
| Spencers Farm Close Management Company Limited | Households | 2024 |
| Sphere Manpower Limited | Administrative & support | 2013 |
| Spice & Spirits Bars Ltd | Hospitality | 2015 |
| Spider Electrical Ltd | Construction | 2006 |
| Spiral Print Studio Limited | Professional & scientific | 2024 |
| Spirit and Sage Counselling and Psychotherapy Ltd | Extraterritorial | 2023 |
| Spirit Mens & Ladies Wear Ltd | Wholesale & retail | 2015 |
| Spiritual Shopping Limited | Professional & scientific | 2003 |
| Spiritual Shopping.Com Limited | Professional & scientific | 2003 |
| Spitfire Coatings Ltd | Public administration | 2026 |
| Splash Estates Ltd | Financial services | 2010 |
| Sportscarcafe Limited | Hospitality | 2007 |
| Spratt Hall Homes Ltd | Real estate | 2015 |
| Springrise Management Limited | Households | 1987 |
| Springtavern Investments Limited | Construction | 1985 |
| Sprint Express UK Limited | Transport & logistics | 2012 |
| SPS Associates Limited | Professional & scientific | 2013 |
| SPV Clarendon Road Devco Ltd | Construction | 2025 |
| SPV Staff Ltd | Real estate | 2018 |
| SPV06 Ltd | Real estate | 2023 |
| Sqpoint Clean Ltd | Administrative & support | 2026 |
| SR PROJECTS1 Ltd. | Construction | 2020 |
| Srelsah 1 Limited | Real estate | 2019 |
| SRM Motors Limited | Wholesale & retail | 2021 |
| SRS Logic Ltd | Information & communication | 2011 |
| Srwg Investments Limited | Real estate | 2023 |
| SS Futures Ltd | Financial services | 2026 |
| SS Trading Consultancy Limited | Professional & scientific | 2025 |
| SS Trading Finance Limited | Administrative & support | 2017 |
| SS Trading Holdings Limited | Real estate | 2017 |
| SSN Group Ltd | Real estate | 2015 |
| SSS Drylining Ltd | Construction | 2009 |
| ST Albans ALE & Cider Investments Limited | Hospitality | 2022 |
| ST Demetrius the Great Martyr | Other services | 2017 |
| ST Edwards Court (Romford) Limited | Construction | 2016 |
| ST James IT Solutions and Consultancy Ltd | Information & communication | 2022 |
| ST Lukes Workspace Limited | Real estate | 2024 |
| ST. James Road Properties Limited | Real estate | 2025 |
| ST. James Technologies Limited | Extraterritorial | 2005 |
| ST. John's Wort Technologies Limited | Information & communication | 2025 |
| St.Marys Lodge Freehold Property Company Limited | Households | 1988 |
| STA Builder Ltd | Construction | 2019 |
| Staarr House LLP | | 2009 |
| Stacey's Tuition Services Limited | Education | 2012 |