| Seed Travel Technology Limited | Information & communication | 2024 |
| Seed Wellness Ltd | Health & social care | 2025 |
| Seeking Perfection Marketing Ltd | Professional & scientific | 2019 |
| Seeking Property Ltd | Real estate | 2019 |
| Seena Solutions Ltd | Information & communication | 2024 |
| Seidai EU Ltd | Wholesale & retail | 2010 |
| Selbest Motors Ltd | Wholesale & retail | 2025 |
| Select Brick Estates Ltd | Real estate | 2016 |
| Selfkind Ltd | Health & social care | 2025 |
| Selleck Properties Limited | Construction | 1977 |
| Selstone Ltd | Wholesale & retail | 2007 |
| Selvagiri Property Ltd | Real estate | 2023 |
| Selway Packaging and Storage Ltd | Administrative & support | 2015 |
| Selwood IT Limited | Administrative & support | 2015 |
| Semor Ltd | Information & communication | 2026 |
| Sendcare Ltd | Education | 2024 |
| Sendswift Ltd | Transport & logistics | 2025 |
| Seneca Tax Limited | Professional & scientific | 2025 |
| Senfuka Emporium Limited | Wholesale & retail | 2026 |
| Senoa Trade Limited | Construction | 2025 |
| Sensation Elle Ltd | Wholesale & retail | 2014 |
| Sense Training and Consultancy Ltd | Education | 2019 |
| Senso Communications Limited | Professional & scientific | 2010 |
| Sensur Ltd | Manufacturing | 2025 |
| Sentry Trading Limited | Wholesale & retail | 2015 |
| SEP Insurance Services Limited | Financial services | 2018 |
| Sequential Synths Limited | Administrative & support | 2022 |
| Serendib Retail London Ltd | Wholesale & retail | 2025 |
| Serendipity Chase Limited | Wholesale & retail | 2023 |
| Service Alpha Beta Limited | Information & communication | 2011 |
| Servologic Limited | Wholesale & retail | 2021 |
| Servwize Solutions Limited | Information & communication | 2022 |
| Sescom Ltd | Manufacturing | 2017 |
| Session Smyth Ltd | Extraterritorial | 2017 |
| Sevenislands Aeolian Concierge Ltd | Hospitality | 2019 |
| Sevenscapes Ltd | Professional & scientific | 2025 |
| Seventh Avenue South Parade Limited | Health & social care | 2017 |
| Severn Ltd | Wholesale & retail | 2024 |
| Severngreen Limited | Real estate | 2022 |
| Seymour Pictures Limited | Administrative & support | 2019 |
| Seymour Taylor Accountants Ltd | Professional & scientific | 2008 |
| Seymour Taylor Audit Limited | Professional & scientific | 1994 |
| Seymour Taylor Limited | Professional & scientific | 2008 |
| SFE Services Ltd | Energy | 2017 |
| SG & Pooks Ltd | Wholesale & retail | 2010 |
| SGH Fabrication Ltd | Manufacturing | 2024 |
| Sgpglobal Limited | Information & communication | 2019 |
| SGS Shutters and Blinds Ltd | Wholesale & retail | 2017 |
| SGT Carpentry Limited | Construction | 2017 |
| SH Engineering Ltd | Manufacturing | 2025 |
| SHA Coolease Ltd | Wholesale & retail | 2025 |
| Shaadisouk Ltd | Other services | 2024 |
| Shadow Corporate Cars Limited | Transport & logistics | 2015 |
| Shadow Executive Cars Limited | Transport & logistics | 2015 |
| Shadwell's Global Limited | Administrative & support | 2009 |
| Shaf Taxis Limited | Transport & logistics | 2021 |
| Shafeens Ltd | Wholesale & retail | 2025 |
| Shah & Sons Partners Ltd | Real estate | 2026 |
| Shah Family Estates Ltd | Real estate | 2024 |
| Shaheen FI LLP | | 2020 |
| Shahji Takeaway Limited | Hospitality | 2026 |
| Shahzadi&Co. Limited | Wholesale & retail | 2025 |
| Shak Automotive Ltd | Wholesale & retail | 2025 |
| Shakehaus Group Limited | Hospitality | 2026 |
| Shakespeare Limited | Information & communication | 2024 |
| Shakespeare Repertory Company Ltd | Education | 2023 |
| Shali Siwa Salt Ltd | Wholesale & retail | 2025 |
| Shane Properties Ltd | Real estate | 2021 |
| Shape London | Health & social care | 1979 |
| Shar Builders Ltd | Construction | 2025 |
| Share Green Ltd | Real estate | 2021 |
| Sharkiss Ltd | Wholesale & retail | 2025 |
| Sharkys Cars Ltd | Wholesale & retail | 2014 |
| Sharlotte Cooper Estates Limited | Real estate | 2026 |
| Sharp IT Services (UK) Limited | Information & communication | 1992 |
| Sharpdeal Limited | Real estate | 1980 |
| Sharpeye Limited | Information & communication | 2015 |
| Shawn DE Souza Limited | Information & communication | 2016 |
| Shayler Ltd | Hospitality | 2018 |
| Shaz Pizza Ltd | Hospitality | 2025 |
| Shazad & Shazad Property Limited | Real estate | 2023 |
| SHE Inspired MEE Limited | Wholesale & retail | 2021 |
| SHE Scales CEO Ltd | Information & communication | 2026 |
| Shean Communications Ltd | Professional & scientific | 2023 |
| Shelburne Heights Residents Company Limited | Households | 1988 |
| Sheldons Construction Ltd | Construction | 2023 |
| Shelley and Millies Hair and Beauty Limited | Other services | 2025 |
| Shemhon Ltd | Information & communication | 2011 |
| Shemp Tech Ltd | Professional & scientific | 2026 |
| Sher Saini Ltd | Professional & scientific | 2025 |
| Sheraton Dwellings Limited | Real estate | 2005 |
| Sheraton Dwellings NO2 Ltd | Real estate | 2014 |
| Sheriff Technology Ltd | Manufacturing | 2001 |
| Sherlockit Ltd | Information & communication | 2025 |
| Sheroz Gold Ltd | Wholesale & retail | 2014 |
| Sherrardswood Holdings Limited | Financial services | 2023 |
| Sherry DEE Limited | Wholesale & retail | 2024 |
| SHH Property Management Ltd | Real estate | 2026 |
| Shidainleather Ltd | Wholesale & retail | 2025 |
| Shield Housing CIC | Administrative & support | 2017 |