| Sky High Developments Ltd | Real estate | 2014 |
| Sky Kitchens & Bedrooms Limited | Manufacturing | 2013 |
| Skycore Technologies Ltd | Wholesale & retail | 2024 |
| Skye Talent Ltd | Professional & scientific | 2021 |
| Skyline Building Merchants Limited | Wholesale & retail | 2020 |
| Skyline Home Developments Limited | Construction | 2025 |
| Skyline Roofing and General Builders Ltd | Construction | 2020 |
| Skyline Transit Ltd | Transport & logistics | 2025 |
| Skyport Cars Limited | Transport & logistics | 2018 |
| Skyport Rentals Ltd | Administrative & support | 2025 |
| Skyport Ride Ltd | Transport & logistics | 2025 |
| Skyspace Holdings 2 Ltd | Real estate | 2026 |
| Skyspace Holdings Ltd | Real estate | 2026 |
| Skyspace International 2 Ltd | Real estate | 2026 |
| Skyspace International Ltd | Real estate | 2026 |
| Skyspace Topco Ltd | Real estate | 2026 |
| Skytouchroofing Ltd | Construction | 2024 |
| Skyview Constructions & Designs Ltd | Construction | 2019 |
| Skyways Roofing Ltd | Construction | 2019 |
| SL4 Ltd | Hospitality | 2018 |
| Slade Film Services Ltd | Arts & recreation | 2024 |
| Slough (Bath Road) Limited | Wholesale & retail | 2003 |
| Slough Estate Solutions Ltd | Other services | 2026 |
| Slough GAS Plus Ltd | Energy | 2016 |
| Slug and Slice Ltd | Hospitality | 2025 |
| SM Aura Ltd | Wholesale & retail | 2025 |
| SM Education London Ltd | Education | 2023 |
| Small Order Springs & Pressings Holdings Limited | Administrative & support | 1998 |
| Small Order Springs & Pressings Limited | Manufacturing | 1986 |
| Smart Adventures Limited | Education | 2016 |
| Smart Brick Block Ltd | Construction | 2020 |
| Smart Developments Hayes Ltd | Real estate | 2026 |
| Smart Exterior Cleaning and Maintenance Limited | Administrative & support | 2011 |
| Smart Glazing & Home Improvements Ltd | Construction | 2017 |
| Smart Heating & Electrics Ltd | Construction | 2018 |
| Smart Heating and Plumbing Services Limited | Construction | 2024 |
| Smart Location Hire Ltd | Construction | 2024 |
| Smart Maintenance and Refurbishments Ltd | Construction | 2025 |
| Smart Mind Health Ltd | Health & social care | 2015 |
| Smart Paint Services Ltd | Construction | 2026 |
| Smart Property Automation Ltd | Information & communication | 2013 |
| Smart Property Projects Ltd | Construction | 2010 |
| Smart Quick Pick Ltd | Wholesale & retail | 2026 |
| Smart Scenery Ltd | Construction | 2021 |
| Smart Services Solution Ltd | Construction | 2025 |
| Smart Tax Services Ltd | Other services | 2024 |
| Smartax Accountancy Ltd | Professional & scientific | 2012 |
| Smash Films Ltd | Arts & recreation | 2018 |
| SMB Project Management Limited | Professional & scientific | 2005 |
| SMB UK Homes Ltd | Real estate | 2025 |
| Smcgstat Ltd | Professional & scientific | 2018 |
| Smile Savers Ltd | Health & social care | 2024 |
| Smith & Daughters Ltd | Manufacturing | 2014 |
| Smiths Fitted Furniture Limited | Construction | 2013 |
| Smiths Fitted Wardrobes & Kitchens Limited | Manufacturing | 2019 |
| Smiths Fitted Wardrobes London Limited | Wholesale & retail | 2018 |
| SMJ Transport U.K. Ltd | Transport & logistics | 2021 |
| Smlc Investments Ltd | Real estate | 2021 |
| SMP Accountants Limited | Professional & scientific | 2013 |
| Smps Tech Ltd | Extraterritorial | 2014 |
| SMS Global Solutions Ltd | Information & communication | 2022 |
| SN LT Ltd | Construction | 2026 |
| Sn&A Services Ltd | Other services | 2014 |
| Snacks Wholesale Limited | Wholesale & retail | 2021 |
| Snap Couriers Ltd | Transport & logistics | 2023 |
| SNJ Consulting Ltd | Education | 2026 |
| Snopake Brands Limited | Wholesale & retail | 2021 |
| Snopake International Limited | Administrative & support | 1995 |
| Snopake Limited | Wholesale & retail | 1987 |
| SNR International Limited | Wholesale & retail | 2019 |
| Soal Ltd | Transport & logistics | 2015 |
| Soax Ltd | Information & communication | 2019 |
| Soccerlogic Ltd | Information & communication | 2011 |
| Social Apex Ltd | Professional & scientific | 2022 |
| Social Care Appropriate Adult Services Limited | Health & social care | 2013 |
| Social Thread Ltd | Professional & scientific | 2025 |
| Society of Laundry Engineers and Allied Trades Limited(The) | Other services | 1907 |
| Society of Nepalese Professionals - UK | Extraterritorial | 2019 |
| Socio Economic Development Forum UK Limited | Other services | 2021 |
| Sofi Properties Limited | Real estate | 2020 |
| Sofia Gegan Limited | Other services | 2007 |
| Soft Clean DRY Cleaners and Laundrette Ltd | Other services | 2026 |
| Soft Creative Limited | Information & communication | 2008 |
| Software Hardware Limited | Administrative & support | 2017 |
| SOH Limited | Financial services | 2007 |
| Sokhi Development Limited | Real estate | 2017 |
| Sokhna Cleaning Limited | Administrative & support | 2025 |
| Soko Properties Limited | Real estate | 2015 |
| Solar Strategic Value Management Limited | Administrative & support | 2018 |
| Solarz Building Sevices Ltd | Construction | 2017 |
| Solex Design Services Limited | Administrative & support | 2013 |
| Solice Consulting Ltd | Health & social care | 2026 |
| Solice.Health Ltd | Professional & scientific | 2020 |
| Solid Crete Ltd | Construction | 2023 |
| Solid Moves Ltd | Transport & logistics | 2019 |
| Solid Power Distribution Ltd | Energy | 2019 |
| Solid Repairs Limited | Construction | 2020 |
| Solista Ltd | Real estate | 2024 |
| Solo GAS Plumbing and Heating Ltd | Manufacturing | 2021 |
| Solpark Limited | Financial services | 2020 |