| Shojae Limited | Information & communication | 2025 |
| Shokudo Ltd | Hospitality | 2024 |
| Shola-Marie's Ltd | Other services | 2026 |
| Shoni Digital Limited | Information & communication | 2023 |
| Shop Flip Limited | Wholesale & retail | 2023 |
| Shop Safari Ltd | Wholesale & retail | 2024 |
| Shopitdirect Ltd | Wholesale & retail | 2024 |
| Shoplogist Limited | Wholesale & retail | 2020 |
| Shopsafe Alert Ltd | Information & communication | 2018 |
| Shopstart Ltd | Wholesale & retail | 2025 |
| Shoptest Ltd | Wholesale & retail | 2025 |
| Shopures Ltd | Wholesale & retail | 2019 |
| Shopwize Distribution & Logistics Ltd | Wholesale & retail | 2024 |
| Shoreditch Ventures Limited | Professional & scientific | 2011 |
| Show Companion Ltd | Information & communication | 2025 |
| Showtime Circus (Events) Ltd | Arts & recreation | 2022 |
| Showtime Circus (Milton Keynes) Ltd | Education | 2022 |
| Showtime Travels Ltd | Transport & logistics | 2025 |
| Shree Isthdeva Limited | Real estate | 2024 |
| Shreegovind Ltd | Construction | 2025 |
| Shrtzstudio Ltd | Wholesale & retail | 2025 |
| Shrubbery Close Management Company Limited | Real estate | 1985 |
| Shshai Ltd | Real estate | 2023 |
| Shugoki Limited | Information & communication | 2025 |
| Shunfatrade Ltd | Wholesale & retail | 2025 |
| Shunputrade Ltd | Wholesale & retail | 2025 |
| Shutter Suffolk Limited | Construction | 2016 |
| SHUTTERS365 Ltd | Other services | 2025 |
| Shuttle Horizons Ltd | Wholesale & retail | 2025 |
| Shychology Ltd | Education | 2025 |
| Shyftr Ltd | Information & communication | 2026 |
| Sibbett Ecology Ltd | Professional & scientific | 2024 |
| Sibria Wholesale and Retail Trading Ltd | Wholesale & retail | 2026 |
| Sicklesmere Stores Ltd | Wholesale & retail | 2014 |
| Sicon Limited | Information & communication | 1999 |
| Side Duck Ltd | Wholesale & retail | 2024 |
| Sidney Roach Lettings & Property Management Limited | Real estate | 2024 |
| Siggers Property Management Ltd | Real estate | 2024 |
| Sigma Business Accountants Ltd | Professional & scientific | 2021 |
| Sigma Business Services Limited | Wholesale & retail | 2018 |
| Sigma Structures Ltd. | Administrative & support | 2017 |
| Signalscope Ltd | Professional & scientific | 2026 |
| Signature Business Solutions Ltd | Wholesale & retail | 2026 |
| SIJ Media Ltd | Professional & scientific | 2024 |
| SIK Productions C.I.C. | Information & communication | 2025 |
| Sikamo Limited | Health & social care | 2023 |
| Silas Network Ltd | Information & communication | 2026 |
| Silenster Building Services Limited | Administrative & support | 2001 |
| Silhouette Security Solutions Ltd | Administrative & support | 2026 |
| Silk Hearts Limited | Wholesale & retail | 2025 |
| Silkstone Printing Ltd | Wholesale & retail | 2025 |
| Sillitoe Property Investments Limited | Real estate | 2025 |
| Silter Insitu Limited | Professional & scientific | 2018 |
| Silver Bear Foods Ltd | Manufacturing | 2025 |
| Silver Mountain Properties Ltd | Information & communication | 2023 |
| Silver Pepper Advisors Limited | Professional & scientific | 2024 |
| Silver River Investments Limited | Real estate | 2026 |
| Silver Stella Limited | Professional & scientific | 2025 |
| Silverain Limited | Construction | 2013 |
| Silvercent Services Limited | Financial services | 2005 |
| Silvergate Consulting Ltd | Information & communication | 2025 |
| Silveris 24 Ltd | Real estate | 2022 |
| Silverline Office Equipment Limited | Manufacturing | 1967 |
| Silverrune Interactive Limited | Wholesale & retail | 2026 |
| Silverwood Shutters Ltd | Construction | 2015 |
| SIM2DO Limited | Manufacturing | 2015 |
| Sima Medical Partners Ltd | Health & social care | 2024 |
| Simkins Holdings Limited | Financial services | 2022 |
| Simon Carmouche Limited | Information & communication | 2016 |
| Simon Frost Transport Ltd | Transport & logistics | 2025 |
| Simon James Ward Ltd | Other services | 2015 |
| Simon Ratcliffe Holdings Limited | Financial services | 2016 |
| Simple Organic 88 Ltd | Wholesale & retail | 2024 |
| Simple Scholar Ltd | Education | 2025 |
| Simple Software Ltd | Information & communication | 2022 |
| Simple System Holdings Limited | Agriculture & fishing | 2024 |
| Simple System Limited | Agriculture & fishing | 1996 |
| Simpler Wipes Ltd | Wholesale & retail | 2024 |
| Simplicity Allure Ltd | Professional & scientific | 2024 |
| Simplifi MED Ltd | Information & communication | 2025 |
| Simplified Relocations Ltd | Real estate | 2023 |
| Simplify Health Ltd | Wholesale & retail | 2026 |
| Simply ADS Ltd | Professional & scientific | 2016 |
| Simply Done Solutions Limited | Information & communication | 2021 |
| Simply Processes Limited | Professional & scientific | 2021 |
| Simply Sorted PA Limited | Administrative & support | 2026 |
| Simply Thrive Services Limited | Administrative & support | 2023 |
| Simplyretailgroup Ltd | Wholesale & retail | 2022 |
| Simpsons Boatyard Ltd | Administrative & support | 2023 |
| Simu.Iq Holding Limited | Financial services | 2026 |
| Sincere Property Services Ltd | Real estate | 2011 |
| Sincerely Carmel Makeup Artistry Ltd | Other services | 2024 |
| Sing Space Choir North LLP | | 2024 |
| Sing Space Choir South LLP | | 2024 |
| Singing Unicorn Ltd | Administrative & support | 2019 |
| Sinoon (UK) Ltd | Wholesale & retail | 2023 |
| Sinosand Trading (Zhejiang) Co., Ltd | Administrative & support | 2021 |
| SIP Happens Coffee Limited | Extraterritorial | 2025 |
| SIP Sisters Mobile Bar Ltd | Hospitality | 2025 |
| Sisel Limited | Health & social care | 2018 |