| Smartfix Group Ltd | Construction | 2025 |
| Smartwave Software Ltd | Information & communication | 2021 |
| Smashing Soundwell Ltd | Hospitality | 2026 |
| SMB Capital Management Ltd | Construction | 2025 |
| SMD Semiconductor UK Limited | Professional & scientific | 2025 |
| Smgreen Invernos Pink Salt Ltd | Wholesale & retail | 2025 |
| Smiljan IPR Limited | Administrative & support | 2020 |
| Smiljan Limited | Manufacturing | 2019 |
| Smiljan Power Solutions Limited | Manufacturing | 2019 |
| Smilyz Medicals Limited | Health & social care | 2023 |
| Smith Creative Design Limited | Other services | 2012 |
| Smith Power Solutions Ltd | Professional & scientific | 2026 |
| Smiths Carpets & Flooring Limited | Wholesale & retail | 2024 |
| SML Thurlestone Limited | Real estate | 2020 |
| Smoke and Fire Ventilation Systems Limited | Manufacturing | 2014 |
| Smokey Burger 165 Ltd | Hospitality | 2025 |
| Smooth Moves Property Agents Limited | Real estate | 2010 |
| Smooth Ride Transport Limited | Transport & logistics | 2026 |
| Smooth Scaffolding Ltd | Construction | 2017 |
| Smoothops 365 Limited | Information & communication | 2026 |
| SMT Aviation Services Limited | Manufacturing | 2022 |
| Smt-Iow Catering Limited | Hospitality | 2021 |
| Smudged Ltd | Professional & scientific | 2022 |
| SMV Innovative Healthcare Limited | Health & social care | 2022 |
| Smwl Limited | Financial services | 2019 |
| SN Foods Ltd | Hospitality | 2024 |
| Snack Shack Newport Ltd | Hospitality | 2019 |
| Snackfit Limited | Administrative & support | 2016 |
| Snake Mountain Studios Limited | Information & communication | 2020 |
| Snapeats Ltd | Transport & logistics | 2025 |
| Snitram Consult and Services Ltd | Professional & scientific | 2025 |
| Snkd Brickwork Limited | Construction | 2019 |
| Snll Investments Ltd | Real estate | 2020 |
| Snma Ltd | Information & communication | 2026 |
| Snowresort Publications Limited | Professional & scientific | 2014 |
| Snug Piercing Studio Ltd | Other services | 2021 |
| SO Exclusive Limited | Manufacturing | 2011 |
| SO What Strategy Ltd | Professional & scientific | 2024 |
| Sober Girl Ltd | Professional & scientific | 2024 |
| Soccer Science Ltd | Education | 2017 |
| Social Buddies Shropshire Ltd | Health & social care | 2026 |
| Social Diamonds Ltd | Wholesale & retail | 2025 |
| Social Researchers of Colour UK CIC | Other services | 2025 |
| Socialey Ltd | Professional & scientific | 2023 |
| Society Newport Ltd | Hospitality | 2021 |
| Sofa Frames Limited | Manufacturing | 2011 |
| Sofa Sofa Limited | Extraterritorial | 2000 |
| Sofasofa Holdco Ltd | Manufacturing | 2024 |
| Sofia Grill Ltd | Hospitality | 2022 |
| Sofierliy Ltd | Wholesale & retail | 2024 |
| Sofinn (UK) Limited | Wholesale & retail | 1981 |
| Sofinn Installation Ltd | Wholesale & retail | 1981 |
| Softwaregoo Limited | Information & communication | 2013 |
| SOH Consulting Limited | Information & communication | 2017 |
| Sojourn Accommodation Limited | Hospitality | 2026 |
| Soku Investments Limited | Real estate | 2026 |
| SOL Renewable Energy Limited | Construction | 2023 |
| Solace Music Ltd | Professional & scientific | 2025 |
| Solace Recruitment Solutions Ltd | Administrative & support | 2023 |
| Solace Talent Ltd | Information & communication | 2023 |
| Solar Bear Energy Solutions Ltd | Manufacturing | 2010 |
| Solar Bear Heatpumps Ltd | Manufacturing | 2010 |
| Solar Heulwen Limited | Construction | 2024 |
| Solar Renewable Installations Ltd | Construction | 2010 |
| Solar Solution (IOW) Ltd | Construction | 2018 |
| Solar Travel Ltd | Transport & logistics | 2025 |
| Solarfields Limited | Real estate | 2011 |
| Solarvolt Renewables Ltd | Construction | 2026 |
| Sole Obsession Ecommerce Ltd | Wholesale & retail | 2026 |
| Solencia Gundogs Ltd | Agriculture & fishing | 2026 |
| Solent (IW) Ltd | Professional & scientific | 2014 |
| Solent Accountancy and Business Services Ltd. | Professional & scientific | 2004 |
| Solent Anaesthesia and Pain Relief Service Ltd | Information & communication | 2018 |
| Solent Community Housing Limited | Households | 2016 |
| Solent Executive Search Ltd | Administrative & support | 2024 |
| Solent Groundworks(Iow) Limited | Construction | 2012 |
| Solent Marine Services Limited | Manufacturing | 2013 |
| Solent Marine Structures Ltd | Construction | 2021 |
| Solent Property Ladder Ltd | Real estate | 2018 |
| Solent Property Solutions Ltd | Real estate | 2018 |
| Solent Residents Company Limited | Households | 2000 |
| Solent Resource Solutions Ltd | Construction | 2021 |
| Solid Lift Solutions Ltd | Administrative & support | 2023 |
| Solin London Ltd | Manufacturing | 2021 |
| Sololyfe Ltd | Manufacturing | 2025 |
| Solster Limited | Information & communication | 2022 |
| Solutia UK Pension Scheme Trustees Limited | Financial services | 1997 |
| Solutions Property Management - South Wales Ltd | Real estate | 2020 |
| Solvo Energy Limited | Construction | 2022 |
| Somerlodge Limited | Professional & scientific | 1993 |
| Somersfoods Limited | Hospitality | 2025 |
| Somerton COD N Chips Ltd | Hospitality | 2019 |
| Somerton Stores Ltd | Wholesale & retail | 2021 |
| Somerton Superstore Ltd | Wholesale & retail | 2025 |
| Sonnyscases Ltd | Wholesale & retail | 2025 |
| Sophic Associates Ltd | Administrative & support | 2021 |
| Sophie's Online Store Ltd | Wholesale & retail | 2023 |
| Sophisticatedd Beauty Limited | Other services | 2020 |
| Sora Growth Limited | Professional & scientific | 2025 |
| Sorbier Limited | Real estate | 2015 |