| Silver Birch Properties Limited | Construction | 2004 |
| Silver FOX Fencing Ltd | Extraterritorial | 2026 |
| Silver Lantern Studios Ltd | Extraterritorial | 2026 |
| Silver Linings Healthcare Ltd | Health & social care | 2026 |
| Silver Number 1 Limited | Wholesale & retail | 2025 |
| Silver Oak International Ltd | Financial services | 2026 |
| Silver OWL Supplies Ltd | Wholesale & retail | 2020 |
| Silver Pine Aria Ltd | Extraterritorial | 2025 |
| Silver Quay Technologies Limited | Extraterritorial | 2026 |
| Silver Saver Limited | Wholesale & retail | 2002 |
| Silver Sprout Ventures Ltd | Extraterritorial | 2026 |
| Silver Store Mini Market Ltd | Wholesale & retail | 2024 |
| Silver Store NO 1 Ltd | Wholesale & retail | 2024 |
| Silver Systems Services Limited | Wholesale & retail | 2024 |
| Silver Transportation Ltd | Transport & logistics | 2019 |
| Silver Trio Ltd | Financial services | 2025 |
| Silverbrook Digital Ltd | Extraterritorial | 2026 |
| Silverist Ltd | Wholesale & retail | 2023 |
| Silverline Nova Ltd | Extraterritorial | 2026 |
| Silverline Quantum Systems Ltd | Extraterritorial | 2025 |
| Silverlined Properties Limited | Real estate | 2019 |
| Silvermere Logistics Limited | Extraterritorial | 2026 |
| Silvermoor Enterprises Ltd | Extraterritorial | 2026 |
| Silveroak Digital Ltd | Extraterritorial | 2025 |
| Silverpeak Innovations Ltd | Extraterritorial | 2026 |
| Silverpine Dynamics Ltd | Extraterritorial | 2026 |
| Silverstone Software Limited | Information & communication | 2018 |
| Silverton Cars Limited | Other services | 2011 |
| Siman Services Ltd | Administrative & support | 2024 |
| Simba Heating Ltd | Construction | 2025 |
| Simba Materials Limited | Manufacturing | 2005 |
| Simcol Holdings Limited | Professional & scientific | 2009 |
| Simeil Properties Ltd | Hospitality | 2021 |
| Simjon Developments Limited | Manufacturing | 1985 |
| Simo's Catering Ltd | Hospitality | 2009 |
| Simon Hallas TM Ltd | Public administration | 2023 |
| Simon Hasan Ltd | Professional & scientific | 2024 |
| Simon Hodgson Plumbing & Heating Services Limited | Construction | 2022 |
| Simon's Car Repairs Limited | Wholesale & retail | 2024 |
| Simoneal Limited | Wholesale & retail | 2021 |
| Simplas Ltd | Water & waste | 2011 |
| Simple AB Ltd | Transport & logistics | 2017 |
| Simple Stuff Property Company Limited | Other services | 2018 |
| Simplex Supplies Limited | Construction | 2011 |
| Simply Clean Team Ltd | Administrative & support | 2026 |
| Simply Frames Ltd | Construction | 2012 |
| Simply Ghost Nights Limited | Arts & recreation | 2012 |
| Simply Motoring Limited | Wholesale & retail | 2022 |
| Simply the Best (Doncaster) Limited | Wholesale & retail | 2020 |
| Simply Transport Limited | Transport & logistics | 2020 |
| SIMPLY2SIMPLESERVERS Ltd | Information & communication | 2026 |
| Sims SMS Ltd | Construction | 2023 |
| Simter Limited | Construction | 2004 |
| Sinamati Facades Ltd | Construction | 2023 |
| Sinapharma Ltd | Wholesale & retail | 2025 |
| Sinead Hald Delaney Property Ltd | Real estate | 2018 |
| SINEM33 Ltd | Hospitality | 2020 |
| Singh Brothers Convenience Store Ltd | Wholesale & retail | 2019 |
| Singh's United Group Limited | Financial services | 2021 |
| Singhs Kitchen Limited | Hospitality | 2024 |
| Singhs Phone Tech and Laundrette Ltd | Wholesale & retail | 2024 |
| Singhss Ltd | Wholesale & retail | 2022 |
| Sino Hats Co., Limited | Professional & scientific | 2010 |
| Sinohas Ltd | Hospitality | 2025 |
| Sinple Doncaster Ltd | Manufacturing | 2022 |
| Siraan Ltd | Real estate | 2020 |
| Sirca Services Ltd | Information & communication | 2024 |
| Siren XYZ Limited | Information & communication | 2024 |
| Sirens Burlesque Ltd | Other services | 2019 |
| Siri Specialist Services Ltd | Information & communication | 2022 |
| Sirius Houses Limited | Real estate | 2022 |
| Sirius Solar Installations Ltd | Construction | 2025 |
| SIS Transport Ltd | Transport & logistics | 2025 |
| Sisi Bawtry Limited | Wholesale & retail | 2019 |
| Sisi Pizza DN1 Ltd | Hospitality | 2022 |
| Sisko Collective Ltd | Education | 2026 |
| SIT Trans Ltd | Transport & logistics | 2020 |
| Site Maintenance Facilities Limited | Other services | 2017 |
| Site Services Management Ltd | Real estate | 2025 |
| Sitelogix Ltd | Information & communication | 2026 |
| Sitwell House Apartments Ltd | Real estate | 2024 |
| Sitwell House Freehold Ltd | Real estate | 2025 |
| SIX Consult Limited | Professional & scientific | 2025 |
| SIX P Projects Limited | Construction | 2022 |
| Sizzlers (Doncaster) Ltd | Hospitality | 2021 |
| SJ & J Johal Ltd | Real estate | 2019 |
| SJ Construction Services Ltd | Construction | 2011 |
| SJ Development Doncaster Ltd. | Construction | 2025 |
| SJ Leisure & Events (Doncaster) Ltd | Other services | 2016 |
| SJ Marshall IT Services Ltd | Information & communication | 2023 |
| SJ Roofing Specialists Ltd | Construction | 2022 |
| SJ Video Ltd | Information & communication | 2011 |
| Sjbn Limited | Information & communication | 2013 |
| SJC Fearn Welding Ltd | Construction | 2026 |
| SJD Properties (Doncaster) Limited | Households | 2016 |
| Sjgp Limited | Wholesale & retail | 2010 |
| Sjgtm Limited | Other services | 2016 |
| SJH Bookkeeping Ltd | Real estate | 2015 |
| SJH Inspections Ltd | Construction | 2024 |
| Sjiri Solutions Ltd | Wholesale & retail | 2026 |