| Sarah Lilly Styling Ltd | Other services | 2019 |
| Sarah Negus Ltd | Other services | 2019 |
| Saratosa Limited | Hospitality | 2003 |
| Sari Pinto Ltd | Administrative & support | 2019 |
| Savage Investments Limited | Construction | 2009 |
| Saxum Enterprises Ltd | Information & communication | 2026 |
| Sayers Commercial Consulting Limited | Administrative & support | 2025 |
| Sayers Commercial Limited | Administrative & support | 2013 |
| SB Ventilation Services Limited | Construction | 2024 |
| SBC Property Consultants Limited | Professional & scientific | 2013 |
| SBM Engineering (Watford) Limited | Administrative & support | 2012 |
| Scafguard Ltd | Administrative & support | 2026 |
| Scale Construction Group Ltd | Construction | 2025 |
| Scale Quickly Ltd | Professional & scientific | 2023 |
| School of Kung FU (Sutton) LLP | | 2019 |
| Sdcs Group Limited | Construction | 2022 |
| SDR Gravel Road Ltd | Real estate | 2023 |
| SDR Properties Limited | Real estate | 2013 |
| SDW Safety Limited | Public administration | 2022 |
| Sea Style Charter Yachts Limited | Transport & logistics | 2017 |
| Sean Moses CIC | Administrative & support | 2010 |
| Seana Educational Consult Limited | Education | 2025 |
| Seaspray Developments Ltd | Real estate | 2020 |
| SEB1980 Ltd | Wholesale & retail | 2023 |
| Seba Cars Ltd | Wholesale & retail | 2013 |
| Sebk Derm Service Ltd | Health & social care | 2024 |
| Secret Singers Limited | Arts & recreation | 2012 |
| Secure Vision Systems Fire and Security Specialists Ltd. | Administrative & support | 2023 |
| SEE England Tour Guide Training Ltd | Education | 2021 |
| Seet London Ltd | Manufacturing | 2023 |
| Selhurst Timber Limited | Wholesale & retail | 2005 |
| Selva Property Group Ltd | Construction | 2026 |
| SEM Facilities Ltd | Extraterritorial | 2018 |
| Semaphore Healthcare Ltd | Professional & scientific | 2019 |
| Semaphore Publications Limited | Wholesale & retail | 1993 |
| Send IT by Ltd | Wholesale & retail | 2022 |
| Seteco Commercial Limited | Real estate | 2022 |
| Shadow Engineering Services Ltd | Professional & scientific | 2025 |
| Shagstone Limited | Professional & scientific | 2016 |
| Shapers (Caterham) Limited | Arts & recreation | 2014 |
| Sharding Ltd | Other services | 2023 |
| Sharon Howland Limited | Administrative & support | 2019 |
| Sharper Labs Academy Ltd | Education | 2021 |
| Sharper Labs Group Ltd | Professional & scientific | 2022 |
| Shaw Court Residents Association Limited | Hospitality | 1965 |
| Shaw FOX Advisory Limited | Information & communication | 2018 |
| Sheehy Building Enterprise Ltd | Real estate | 2020 |
| Shellmark Building Services Ltd | Construction | 2014 |
| Shenghe Mingde (UK) Ltd | Real estate | 2020 |
| Sherwood Park Estates Limited | Real estate | 2008 |
| SHG Intl Consulting Limited | Other services | 2018 |
| Shipley Travel Ltd | Administrative & support | 2010 |
| Shirley Park Solutions Limited | Construction | 2014 |
| Shirley Road Limited | Real estate | 2026 |
| Shokh UK Limited | Wholesale & retail | 2024 |
| Shontaessmocks Ltd | Wholesale & retail | 2025 |
| Shorter Stock Limited | Real estate | 2023 |
| Shortland and Sawbridge Probate Limited | Professional & scientific | 2015 |
| Sidney Llewellyn Limited | Real estate | 2003 |
| Sierra Tango Flying Group Limited | Transport & logistics | 2019 |
| Sigma Fund Management LLP | | 2008 |
| Silver Tongue Scenery Limited | Manufacturing | 2013 |
| Silvermere Limited | Professional & scientific | 2014 |
| Silverred Limited | Real estate | 2018 |
| Silverwood Investment Holdings Limited | Financial services | 2026 |
| Simjee Moosa & Co Ltd | Households | 2026 |
| Simple Grass Limited | Construction | 2015 |
| Simply Windows and Doors Ltd | Construction | 2026 |
| Simulate Limited | Information & communication | 2022 |
| Singleton Homes Limited | Construction | 2021 |
| Sisyphus Investment Bank IT Solutions Limited | Information & communication | 2003 |
| Site Authorisation Services Ltd | Professional & scientific | 2019 |
| Siteclear Ltd | Water & waste | 2021 |
| SIX Point 2 Limited | Information & communication | 2026 |
| SJ Training Services Ltd | Construction | 2025 |
| Skaterham | Arts & recreation | 2012 |
| Skillmonger Limited | Administrative & support | 2022 |
| Skin and Wellness Ltd | Other services | 2026 |
| Skin to Glow Ltd | Wholesale & retail | 2020 |
| Slalom Resourcing Ltd | Administrative & support | 2019 |
| Sloane Stablebridge Creative Ltd | Professional & scientific | 2013 |
| SM Pet Supplies Limited | Wholesale & retail | 2025 |
| Smart in Capital LLP | | 2014 |
| Smart in Financial Ltd | Financial services | 2014 |
| Smart in Group Ltd | Financial services | 2023 |
| Smart in Hotels Ltd | Hospitality | 2023 |
| Smart in Property Ltd | Real estate | 2002 |
| Smart in Regeneration LLP | | 2014 |
| Smart Shelta Ltd | Other services | 2021 |
| Smartech Consultants Ltd | Other services | 2021 |
| Smartsparks London Limited | Construction | 2016 |
| Smas Consultancy Limited | Professional & scientific | 2019 |
| Smiles by Anni Limited | Health & social care | 2018 |
| Smith & Goddard Ltd | Extraterritorial | 2021 |
| Smith & SON Group Limited | Construction | 2025 |
| Smith & SON Plastering Limited | Construction | 2022 |
| SMK Healthcare Ltd | Wholesale & retail | 2020 |
| Snap Shot Productions Ltd | Arts & recreation | 2018 |
| Snazzy Services Limited | Other services | 2000 |
| Snow Creative Limited | Professional & scientific | 2005 |