| Scolchem Limited | Real estate | 1984 |
| Scope Building Consultants Limited | Construction | 2002 |
| Scopesoma Limited | Administrative & support | 2024 |
| Scott Kimble Ltd | Professional & scientific | 2017 |
| Screed Force Contractors Ltd | Construction | 2025 |
| Screensavers Pc's Limited | Information & communication | 2003 |
| Sdstm Properties Ltd | Real estate | 2020 |
| SE London Tennis Ltd | Arts & recreation | 2022 |
| Seabream Properties Ltd | Real estate | 2018 |
| Second City TA Ltd | Construction | 2019 |
| Second Ocean Park Management Co. Limited | Households | 1993 |
| Seculla Technologies Ltd | Information & communication | 2025 |
| Securesquad Ltd | Information & communication | 2023 |
| Security Search Management & Solutions Limited | Public administration | 2010 |
| Sedel Consulting Ltd | Information & communication | 2015 |
| Seeking Itinerary UK Ltd | Administrative & support | 2019 |
| Sefgrove Limited | Wholesale & retail | 1975 |
| Select Air Management Ltd | Construction | 2017 |
| Seleta Training and Personnel Services Limited | Professional & scientific | 1989 |
| Sellersmart Ltd | Wholesale & retail | 2024 |
| Senna Power Systems Limited | Construction | 2025 |
| Sequin KAY Art Ltd | Arts & recreation | 2024 |
| Serendipity Pictures Ltd | Information & communication | 2025 |
| Serene Ventures LLP | | 2021 |
| Serenity Builders Ltd | Construction | 2025 |
| Servicecore Consulting Limited | Professional & scientific | 2026 |
| SET Priced Ltd | Construction | 2025 |
| Setcrown Limited | Professional & scientific | 2008 |
| Sevenhills Homes Ltd | Real estate | 2020 |
| SEVENTY6 Holdings Ltd | Real estate | 2024 |
| Sfizer Global Solutions Limited | Information & communication | 2014 |
| SGC54 Ltd | Information & communication | 2022 |
| Shalebury Properties Ltd | Real estate | 2006 |
| Shan Frying Ltd | Hospitality | 2020 |
| Shandys Mobile Bar Ltd | Wholesale & retail | 2024 |
| Shannan Electrical Services Ltd | Construction | 2021 |
| Sharon Jenson Childminding Service Ltd | Health & social care | 2019 |
| Sharp & Simpson Ltd | Other services | 2017 |
| Shawclean (Plumstead) Limited | Other services | 1973 |
| Sheerclass Wheels and Tyres Ltd | Wholesale & retail | 2011 |
| Sherbets Minicabs Ltd | Transport & logistics | 2022 |
| Sherwood Property Investments Limited | Financial services | 2017 |
| Shiraz Lotus Ltd | Real estate | 2021 |
| Shiv Pooja Trading Limited | Wholesale & retail | 2013 |
| Shoe Doctor Ltd | Other services | 2019 |
| Shopy Media LLP | | 2026 |
| Shoreditch Events Company Ltd | Hospitality | 2012 |
| Shorus Panels Ltd | Wholesale & retail | 2025 |
| Shray IT Solutions Ltd | Information & communication | 2018 |
| Shree Cleaning Ltd | Other services | 2014 |
| Shrieves Consulting Ltd | Professional & scientific | 2016 |
| Shrimpton Services Ltd | Real estate | 2016 |
| Shua Marketing Ltd | Information & communication | 2026 |
| SHUFENG328 Ltd | Hospitality | 2018 |
| Shumber Consulting Limited | Administrative & support | 2025 |
| Sibios-It Consulting Limited | Administrative & support | 2011 |
| Sibor Solutions Ltd | Construction | 2023 |
| Siccura Ltd | Information & communication | 2011 |
| Sicura Migrations Limited | Professional & scientific | 2021 |
| Sidcup Healthcare Plus Ltd | Health & social care | 2025 |
| Sidcup Windows and Doors Ltd | Manufacturing | 2005 |
| Sidney Curtis Financial Limited | Financial services | 2022 |
| SIF Property Limited | Extraterritorial | 2018 |
| Sigma Healthcare Solutions Ltd | Health & social care | 2022 |
| Signalite Limited | Manufacturing | 2014 |
| Silver FOX Micro PUB Ltd | Hospitality | 2019 |
| Silversky Construction Ltd | Construction | 2018 |
| Silverspoon Blossom House Limited | Hospitality | 2023 |
| Simfinity Limited | Wholesale & retail | 2024 |
| Simms Building and Civil Engineering Ltd | Construction | 2017 |
| Simply Construction & Consultancy Ltd | Construction | 2024 |
| Simply Eco South East Ltd | Construction | 2023 |
| Singway 2 Limited | Professional & scientific | 2010 |
| SJ3 Investments Limited | Real estate | 2017 |
| SJC Consulting Sevenoaks Ltd | Professional & scientific | 2018 |
| Sjdecorating Limited | Construction | 2021 |
| SK Management London Limited | Administrative & support | 2019 |
| Skillbase Group Ltd | Administrative & support | 2018 |
| Skkr Investments Limited | Financial services | 2026 |
| SKO Investment Holdings Ltd | Real estate | 2021 |
| SKS Homes Ltd | Real estate | 2015 |
| Sky Dental Clinic Ltd | Health & social care | 2021 |
| Sky Health Clinic Ltd | Health & social care | 2024 |
| Sky Homes (London) Ltd | Construction | 2023 |
| Skyline Lettings Ltd | Real estate | 2000 |
| SL Community Limited | Education | 2025 |
| Slades Livery Stables Limited | Arts & recreation | 2014 |
| Slhf Consulting Ltd | Professional & scientific | 2023 |
| Sloo Ltd | Administrative & support | 2020 |
| Slowe Studio Ltd | Wholesale & retail | 2025 |
| Smart Cosmetics Ltd | Administrative & support | 2025 |
| Smart Flow Heating Limited | Construction | 2023 |
| Smart Global Ltd | Administrative & support | 2015 |
| Smart Integration Solutions Ltd | Professional & scientific | 2022 |
| Smart Plumbing Solutions Limited | Construction | 2014 |
| Smarts Build Limited | Construction | 2020 |
| SMC Design and Build Co. Ltd | Construction | 2024 |
| Smile 101 Limited | Health & social care | 2010 |
| Smilee Support Services Limited | Health & social care | 2017 |
| Smith & SON Tax Ltd | Professional & scientific | 2019 |