| Showstar Limited | Wholesale & retail | 1989 |
| SIG Father Ltd | Professional & scientific | 2023 |
| Silcock Investments Limited | Households | 2025 |
| Since YOU ASK ME Limited | Arts & recreation | 2018 |
| Sirene Fisheries Limited | Agriculture & fishing | 2026 |
| Sirplantalot Ltd | Administrative & support | 2019 |
| Sister Scissors Ltd | Other services | 2008 |
| Sisters Garden Limited | Professional & scientific | 2022 |
| Site Temps Ltd | Extraterritorial | 2022 |
| Sixat Ltd | Extraterritorial | 2024 |
| SJB Automotive Limited | Wholesale & retail | 2022 |
| SJN Management Company Limited | Professional & scientific | 2013 |
| SJP Services Kent Limited | Transport & logistics | 2022 |
| SK4SCAFFOLDING Ltd | Construction | 2023 |
| Skatermate Ltd | Administrative & support | 2013 |
| Skinnersonline Ltd | Health & social care | 2023 |
| Sklr Heritage | Transport & logistics | 2009 |
| Sky JOB Ltd | Administrative & support | 2015 |
| Skyline Building Contractors Ltd | Construction | 2018 |
| Skyline Rail Ltd. | Construction | 2014 |
| Skystraits Ltd | Transport & logistics | 2025 |
| SLC EU Holdings Limited | Professional & scientific | 2026 |
| Smallfilms Limited | Arts & recreation | 2010 |
| Smart East West Ltd | Manufacturing | 2015 |
| Smart Solutions (MS) Limited | Education | 2011 |
| Smarter 360 Ltd | Information & communication | 2026 |
| Smartspeak Limited | Administrative & support | 2014 |
| SMC Projects London Limited | Professional & scientific | 2021 |
| Smero Consulting Ltd | Real estate | 2026 |
| Smilecare Group Ltd | Health & social care | 2022 |
| Smtf Ltd | Financial services | 2023 |
| Sneeze Solutions Limited | Financial services | 2016 |
| SO Pink Academy Ltd | Education | 2024 |
| SO Pink Ltd | Other services | 2020 |
| SO Solid Screw Ltd | Construction | 2022 |
| Socializer Ltd | Administrative & support | 2024 |
| Sociallabs Enterprises Ltd | Professional & scientific | 2025 |
| Soft Service Solutions Ltd | Administrative & support | 2022 |
| Solar Air (UK) Limited | Construction | 2011 |
| Solar Shield Blinds Limited | Other services | 2004 |
| Solis Green Solutions Ltd | Energy | 2024 |
| Solo Refurbishments Ltd | Construction | 2024 |
| SOLUTIONS4VITALITY Ltd | Construction | 2018 |
| SON Light Healing Ltd | Wholesale & retail | 2024 |
| Sonia Tech London Ltd | Financial services | 2024 |
| Sonography South East Limited | Administrative & support | 2013 |
| Sooshi Sushi Ltd | Hospitality | 2021 |
| Sophie Proofreads Ltd | Administrative & support | 2024 |
| Soul Cafe Whitstable Ltd | Hospitality | 2026 |
| Souper Food Catering Ltd | Hospitality | 2023 |
| Source of Sounds Events Ltd | Arts & recreation | 2026 |
| South East Cladding Ltd | Construction | 2025 |
| South East Composite Doors Limited | Construction | 2016 |
| South East Parks Holdings Limited | Financial services | 2025 |
| South Lodge Residents Limited | Administrative & support | 2004 |
| South Park Village Management Company Limited | Households | 1992 |
| Southall Holdings Limited | Real estate | 2020 |
| Southeast Sailboats Ltd | Wholesale & retail | 2018 |
| Southern HV Ltd | Professional & scientific | 2024 |
| Southern Septic Surveyors Ltd | Construction | 2010 |
| Sparkes Elite Electrical Ltd | Construction | 2025 |
| Spartan Aluminium Limited | Administrative & support | 2020 |
| Special Parts Limited | Professional & scientific | 2018 |
| Specialist Mechanics Limited | Wholesale & retail | 2024 |
| Specialist Technical Resources Limited | Administrative & support | 2022 |
| Spectacular Skin Care Limited | Other services | 2020 |
| Spectra Strip Limited | Extraterritorial | 1980 |
| Speedy Tyre Services Limited | Wholesale & retail | 2024 |
| Spencer Paul Golf Ltd | Wholesale & retail | 2016 |
| Spire Court Limited | Real estate | 2018 |
| Spirituality Ltd | Other services | 2012 |
| Springboard Services Ltd | Health & social care | 2018 |
| Springfield Catering Management Ltd | Hospitality | 2018 |
| Squeaky Wheel Children's Theatre CIC | Arts & recreation | 2025 |
| SR Portfolio Limited | Real estate | 2018 |
| ST Jacobs Management Company Limited | Households | 2004 |
| ST Martin's Court (Canterbury) Limited | Real estate | 2001 |
| ST Stephens House Freeholders Limited | Households | 1999 |
| ST. Alphege Court Management Company Limited | Households | 1990 |
| ST. Oate Ltd | Real estate | 2015 |
| Stack Publishing Limited | Professional & scientific | 2020 |
| Stafford Place Consulting Limited | Professional & scientific | 2012 |
| Staincliffe View Management Company Limited | Households | 2003 |
| Stanley Bay Limited | Financial services | 2020 |
| Stave Productions Ltd | Information & communication | 2024 |
| Stay Atelier Ltd | Real estate | 2024 |
| Stay Makers Ltd | Construction | 2024 |
| Steadicam Limited | Information & communication | 2020 |
| Steadmills Glazing Solutions Ltd | Construction | 2025 |
| Stealth Performance Ltd | Administrative & support | 2025 |
| Stella O'Farrell Ltd | Other services | 2020 |
| Stellar Productions Ltd | Arts & recreation | 2010 |
| Stern Slices Limited | Hospitality | 2024 |
| Steve Austin Ltd | Information & communication | 2013 |
| STH Construction & Engineering Ltd | Professional & scientific | 2025 |
| Stone Deluxe Ltd | Manufacturing | 2025 |
| Stoptalking Photography Ltd | Professional & scientific | 2014 |
| STORY22 Ltd | Manufacturing | 2020 |
| Strand Street Kitchen & Bar Ltd | Hospitality | 2023 |
| Street Kings Smoke Shack Ltd | Hospitality | 2018 |