| Semmelweis Care Solutions Ltd | Health & social care | 2024 |
| Send Inspire Ltd | Education | 2015 |
| Sentinel Strategies Ltd | Hospitality | 2026 |
| Seven Freight Ltd | Transport & logistics | 2020 |
| SGL Cleaning Services Stowmarket Limited | Administrative & support | 2025 |
| SH Specialist Cars Ltd | Wholesale & retail | 2024 |
| Shadow Gallery Limited | Other services | 2025 |
| Shaobinwu Ltd | Health & social care | 2021 |
| Shapes and Fables Ltd | Professional & scientific | 2024 |
| Shark Infested Custard Ltd | Information & communication | 2013 |
| Sharkey-Kung Consulting Limited | Professional & scientific | 2019 |
| Sharp Carpentry & Building Limited | Construction | 2014 |
| Sharpe Heating Limited | Construction | 2014 |
| SHE Refurb Ltd | Construction | 2026 |
| Shellyn Ltd | Wholesale & retail | 2022 |
| Shelmore Developments Limited | Construction | 2010 |
| Shelmore Property Management Services Limited | Construction | 2020 |
| Shield Engineering Services Limited | Administrative & support | 1991 |
| Shining Leafs Ltd | Transport & logistics | 2024 |
| Shmunky Finance Ltd | Real estate | 2023 |
| Shmunky Limited Liability Partnership | | 2017 |
| Shree Logic Systems Ltd | Information & communication | 2026 |
| Shumira Care Ltd | Information & communication | 2019 |
| Sidney Restorations Limited | Construction | 2024 |
| Sigurd Commercial Limited | Real estate | 2018 |
| Sigurd Investments Limited | Real estate | 2015 |
| Sila Kebab Ltd | Hospitality | 2023 |
| Silver FOX Tractor Spares Limited | Wholesale & retail | 2009 |
| Silver Hills Estates Limited | Agriculture & fishing | 2024 |
| Silvy Abel Sabu Limited | Real estate | 2024 |
| Simply Money Limited | Financial services | 2000 |
| Simply Moving Ltd | Extraterritorial | 2018 |
| Simply Superb Limited | Health & social care | 2014 |
| SIP & Savour Hospitality Ltd | Hospitality | 2025 |
| Sippin Pretty Ltd | Arts & recreation | 2025 |
| Site Ready Services Limited | Administrative & support | 2026 |
| Site Sweeper Services Ltd | Construction | 2018 |
| Skew Piebald Limited | Hospitality | 2014 |
| Skye Mobiles Ltd | Wholesale & retail | 2026 |
| Skytop Scaffolding Limited | Construction | 2025 |
| Sleeping Phpg Holdings Limited | Financial services | 2025 |
| Sllp Prop Co Limited | Real estate | 2022 |
| Smallsee Limited | Professional & scientific | 2022 |
| Smart Carpentry & Building Services Limited | Construction | 2018 |
| Smart Media Sales Ltd | Professional & scientific | 2026 |
| Smartpet Technology Limited | Wholesale & retail | 2021 |
| SMG Property Services Limited | Construction | 2012 |
| Smith & Co Properties Ltd | Construction | 2017 |
| Smithshire Ltd | Real estate | 2023 |
| SML Cars UK Ltd | Wholesale & retail | 2024 |
| Snori Consultancy Limited | Professional & scientific | 2013 |
| Snowdrop Lewes Ltd | Hospitality | 2025 |
| Snubsmedia Ltd | Wholesale & retail | 2025 |
| Soames & Co Services Limited | Construction | 2020 |
| Soar Ace Limited | Administrative & support | 2023 |
| Softwired Ltd | Professional & scientific | 2026 |
| Softwood Books Ltd | Information & communication | 2026 |
| Soil Remediation UK Ltd | Water & waste | 2015 |
| Solidboss Worldwide UK Limited | Wholesale & retail | 2019 |
| Sonika Ltd | Health & social care | 2021 |
| Soul City Records Limited | Wholesale & retail | 2025 |
| SOW Successful Limited | Agriculture & fishing | 2020 |
| SP Capital Limited | Professional & scientific | 2025 |
| SP Suffolk Limited | Transport & logistics | 2006 |
| Space Connections Limited | Real estate | 2025 |
| Space Consulting Structural Engineers Limited | Professional & scientific | 2015 |
| Spark Innovations Limited | Administrative & support | 2018 |
| Sparkle & Shine Suffolk Ltd | Administrative & support | 2023 |
| Sparrowhawk's Convenience Stores of Stowmarket Ltd | Wholesale & retail | 2022 |
| SPATIALPRO365 Solutions Ltd | Information & communication | 2024 |
| SPD Plasterers Limited | Construction | 2020 |
| Specto Natura Limited | Professional & scientific | 2008 |
| Spencer Hospitality Limited | Hospitality | 2016 |
| Spinning House Design Studio Limited | Professional & scientific | 2014 |
| Spinning House Investment Property Limited | Real estate | 2016 |
| SPM (Stores) Ltd | Wholesale & retail | 2010 |
| Spmp Holdings Limited | Professional & scientific | 2003 |
| Spmu & Lashes by Heidi Green Limited | Other services | 2018 |
| Spondle Limited | Professional & scientific | 2007 |
| Spring Tide Group Limited | Professional & scientific | 2021 |
| Springate Advisory Limited | Professional & scientific | 2011 |
| Springfield Auto Sales Limited | Wholesale & retail | 2025 |
| Spritely Osteopathy Limited | Health & social care | 2015 |
| SRB Svcs Ltd | Administrative & support | 2022 |
| SS Skin Medical Aesthetics Ltd | Other services | 2022 |
| ST Johns Barns Management Limited | Households | 2022 |
| STAND4 Ventures Ltd. | Wholesale & retail | 2017 |
| Stannards(Stowmarket)Limited | Wholesale & retail | 1961 |
| Stantheatre Ltd | Arts & recreation | 2026 |
| Startline Fitness Limited | Professional & scientific | 2018 |
| Station Autoworks Limited | Wholesale & retail | 2026 |
| Station Styles Limited | Other services | 2025 |
| Statsmart Ltd | Information & communication | 2025 |
| Stem Explored Limited | Professional & scientific | 2015 |
| Stephanie Norris Architects Limited | Professional & scientific | 2019 |
| Stephen Barker Garden Machinery Limited | Wholesale & retail | 2018 |
| Sterling Safety & Risk Services (Ssrs) Limited | Professional & scientific | 2018 |
| Steve Joy Development Limited | Professional & scientific | 2023 |
| Steven R Francis & Co Limited | Professional & scientific | 2003 |
| Stone Rose Crystals Limited | Wholesale & retail | 2015 |