| Simple Management Ltd | Information & communication | 2026 |
| Simple Self Defence Ltd | Information & communication | 2024 |
| Simpleuptime Ltd | Information & communication | 2025 |
| Simplicity Recipe Ltd | Professional & scientific | 2022 |
| Simplinutrition Ltd | Wholesale & retail | 2024 |
| Simply 4 Design Ltd | Wholesale & retail | 2019 |
| Simply Acquisitions Limited | Professional & scientific | 2024 |
| Simply Ascent Ltd | Wholesale & retail | 2018 |
| Simply Automotive Ltd | Wholesale & retail | 2015 |
| Simply Beau Relocations Ltd | Hospitality | 2023 |
| Simply BED Investments Limited | Financial services | 2025 |
| Simply Ecommerce Ltd | Extraterritorial | 2014 |
| Simply GEE Property Solutions Ltd | Construction | 2021 |
| Simply Hamber Properties Ltd | Real estate | 2021 |
| Simply Just Parts Limited | Wholesale & retail | 2026 |
| Simply Properties Poole Ltd | Real estate | 2020 |
| Simply Tiger Ltd | Wholesale & retail | 2020 |
| Simply Vendee Ltd | Real estate | 2017 |
| Simplyforevergifts Ltd | Wholesale & retail | 2025 |
| Simpson Technical Recruitment Limited | Manufacturing | 2019 |
| Simpsons Investment Ltd | Real estate | 2021 |
| Simsek Trading Ltd | Wholesale & retail | 2011 |
| Simul Group Limited | Financial services | 2020 |
| Since Ninety Three Ltd | Professional & scientific | 2020 |
| Sinclair Boat Services Ltd | Transport & logistics | 2021 |
| Sinclair Energy Partners Ltd | Professional & scientific | 2018 |
| Sindh Distro Ltd | Wholesale & retail | 2025 |
| Single PLY Roofing Limited | Construction | 2013 |
| Single Storey Design Ltd | Construction | 2024 |
| Singlehub Limited | Information & communication | 2025 |
| Singlepoint Bookkeeping Services Limited | Administrative & support | 2010 |
| Singleton Accountants and Consultancy Ltd | Professional & scientific | 2024 |
| Singularity Publishing Ltd | Information & communication | 2025 |
| Sipstrassi Ltd | Other services | 2019 |
| Siren Marketing Ltd | Professional & scientific | 2024 |
| Siryn Limited | Professional & scientific | 2008 |
| SIS Interiors Ltd | Construction | 2018 |
| SIT Stay Shop at Grooming Marvellous Ltd | Wholesale & retail | 2026 |
| Site Squad Ltd | Information & communication | 2025 |
| Site Transit Limited | Construction | 2013 |
| Sitevis Ltd | Information & communication | 2024 |
| Sitewear UK Ltd | Wholesale & retail | 2025 |
| Sitters Limited | Administrative & support | 1999 |
| Sivar's CUT Ltd | Other services | 2024 |
| Siviter Property Management Limited | Real estate | 2025 |
| SIX Enterprises Limited | Professional & scientific | 2014 |
| SIYARAM2025 Limited | Wholesale & retail | 2025 |
| SJ Events Limited | Arts & recreation | 2014 |
| SJC Brickwork 57 Ltd | Construction | 2012 |
| SJC Flooring Ltd | Construction | 2024 |
| SJC Poole LLP | | 2024 |
| SJD Scaffolding Limited | Construction | 2024 |
| Sjjm Enterprises Limited | Professional & scientific | 2014 |
| SJM Advisors Ltd | Financial services | 2020 |
| SJP Distribution Ltd | Wholesale & retail | 2025 |
| SJP Roofing & Solar Ltd | Construction | 2023 |
| SJP Roofing Ltd | Construction | 2018 |
| Sjpf Property Limited | Real estate | 2026 |
| SJR Legal Services Limited | Professional & scientific | 2018 |
| SJV Aviation Ltd | Manufacturing | 2024 |
| SJW Holdings Limited | Financial services | 1998 |
| SK ALL in One Shop Ltd | Wholesale & retail | 2025 |
| SK Wallisdown Ltd | Other services | 2025 |
| Skaza Construction Limited | Construction | 2025 |
| Skelio Digital Ltd | Information & communication | 2025 |
| SKI Boots & Flip Flops Ltd | Professional & scientific | 2023 |
| Skillbridge Innovations Ltd | Information & communication | 2025 |
| Skin App Limited | Extraterritorial | 2020 |
| Skin Cancer Symposiums UK Limited | Administrative & support | 2018 |
| Skin Within Group Limited | Health & social care | 2022 |
| Skld Ltd | Information & communication | 2020 |
| SKS Retail Group Ltd | Wholesale & retail | 2020 |
| Skw-Jessicaaesthetics Ltd | Health & social care | 2025 |
| Sky Clicks Limited | Wholesale & retail | 2025 |
| Sky High Gymnastics Ltd | Arts & recreation | 2024 |
| Skybound Wealth Management Limited | Professional & scientific | 2002 |
| Skycap Consultancy Limited | Professional & scientific | 2025 |
| Skydive Nimsdai Ltd | Arts & recreation | 2023 |
| Skyeton Prevail Solutions Limited | Manufacturing | 2025 |
| Skyfielder Ltd | Professional & scientific | 2022 |
| Skylark and Bain Limited | Information & communication | 2025 |
| Skylark Dorset Ltd | Real estate | 2025 |
| Skyline Sound Limited | Information & communication | 2025 |
| Skyloh Lettings Limited | Administrative & support | 2025 |
| Skynanny Ltd | Information & communication | 2026 |
| Skyray Management Ltd | Professional & scientific | 2026 |
| Skyside Limited | Hospitality | 2022 |
| Skyvax Ltd | Administrative & support | 2022 |
| SL & Co Events Limited | Administrative & support | 2025 |
| Slabgroup Ltd | Hospitality | 2025 |
| Slamdunk Group Ltd | Real estate | 2020 |
| Slammin' Sauces Ltd | Manufacturing | 2025 |
| SLB One Group Limited | Professional & scientific | 2024 |
| SLE Professional Services Ltd | Professional & scientific | 2023 |
| Sleepdreamsteepees Ltd | Hospitality | 2025 |
| Sleepthru Ltd | Manufacturing | 2022 |
| Sleeve Notes Music Limited | Wholesale & retail | 2026 |
| Slepe Farm Limited | Agriculture & fishing | 1975 |
| SLHOMES4YOU Ltd | Construction | 2025 |
| Slimthic Ltd | Wholesale & retail | 2025 |