| S Leach Plumbing & Heating Ltd | Construction | 2025 |
| S M Ahmad Colorectal Consultant UK Ltd | Health & social care | 2009 |
| S Mono Properties Ltd | Real estate | 2023 |
| S P Ward Holmes Limited | Real estate | 2026 |
| S R Auto Refurbishments Ltd | Wholesale & retail | 2018 |
| S R Preston Limited | Health & social care | 2010 |
| S Richardson Railways Limited | Construction | 2018 |
| S Sodhi Projects Ltd | Professional & scientific | 2026 |
| S Swaby Joinery Ltd | Construction | 2021 |
| S Thomas (Public House) Limited | Hospitality | 2017 |
| S. Dahiya Limited | Health & social care | 2013 |
| S. Smith & Co Accountants Limited | Professional & scientific | 2008 |
| S. Spavin Limited | Transport & logistics | 1973 |
| S.A.N. Security Ltd | Professional & scientific | 2021 |
| S.A.S Garage Doors & Shutters Ltd | Construction | 2021 |
| S.G.D. Construction Limited | Construction | 1994 |
| S.H. Brown (Farms) Limited | Agriculture & fishing | 1973 |
| S.M (Scunthorpe) Limited | Real estate | 2017 |
| S.W.R Multiserv Ltd | Transport & logistics | 2025 |
| SA Fire Safety Ltd | Administrative & support | 2018 |
| SA Taylor Imaging Limited | Health & social care | 2018 |
| SA Vending Ltd | Wholesale & retail | 2025 |
| Sabeni Trading Limited | Manufacturing | 2019 |
| Sabr Holdings Ltd | Real estate | 2021 |
| SAC Pharma Services Ltd | Professional & scientific | 2015 |
| Sadia Javaid Limited | Health & social care | 2023 |
| Saether & Smith Developments Ltd | Construction | 2025 |
| Safe Equestrian - Inclusion for ALL CIC | Education | 2024 |
| Safe Equestrian - Learning With Horses Ltd | Agriculture & fishing | 2023 |
| Safe Tuition Limited | Agriculture & fishing | 2023 |
| Safecare Network Limited | Health & social care | 2003 |
| Safenet Solutions Limited | Administrative & support | 2016 |
| Saferoad UK Ltd | Construction | 2006 |
| Saferoad VRS Ltd | Construction | 2006 |
| Safesite Environmental Limited | Administrative & support | 2008 |
| Safespace Traffic Management Ltd | Construction | 2023 |
| Safety Monkey Ltd | Professional & scientific | 2024 |
| Sahak Property Ltd | Real estate | 2020 |
| Sakuramon Cards Ltd | Wholesale & retail | 2025 |
| Salnose Limited | Health & social care | 2023 |
| Salzburg Limited | Wholesale & retail | 2024 |
| SAM and MAG Cafe Ltd | Hospitality | 2025 |
| SAM Maintenanc Limited | Real estate | 2024 |
| Samaters Transport Ltd | Transport & logistics | 2026 |
| SAMAX909 Limited | Manufacturing | 2024 |
| Samson Network Services Ltd. | Information & communication | 2017 |
| SAN DO Takeaway Limited | Hospitality | 2020 |
| SAN Pietro Restaurants Limited | Hospitality | 2003 |
| Sandhu Property Investments Lincolnshire Ltd | Construction | 2026 |
| Sandmarsh Renovations Ltd | Construction | 2025 |
| Sandtoft Trade Centre Limited | Wholesale & retail | 2017 |
| Sansar Medical Limited | Health & social care | 2014 |
| Sansz Ltd | Real estate | 2025 |
| Santho &Co Limited | Health & social care | 2015 |
| Sara Original Limited | Wholesale & retail | 2019 |
| Sarah Wiseman Ltd | Hospitality | 2021 |
| Sarma Retail Ltd | Wholesale & retail | 2022 |
| Sart Convenience Ltd | Wholesale & retail | 2016 |
| SAS Active Ltd | Administrative & support | 2017 |
| SAS Convenience Store Ltd | Wholesale & retail | 2024 |
| SAS Investment Portfolio Limited | Real estate | 2013 |
| Saunby Ltd | Professional & scientific | 2025 |
| SAW Express Limited | Wholesale & retail | 2023 |
| Saxon Quality Foods Limited | Manufacturing | 2010 |
| SBR (Scunthorpe) Limited | Administrative & support | 2019 |
| SBR Energy Ltd | Agriculture & fishing | 2024 |
| SBR Group Developments Limited | Real estate | 2018 |
| SBR Heavy Haulage Limited | Transport & logistics | 2025 |
| SBR Hire Ltd | Agriculture & fishing | 2024 |
| SBR Land Developments Ltd | Construction | 2025 |
| SBR Plant Hire Limited | Administrative & support | 2019 |
| SBR Sylhet Limited | Water & waste | 2025 |
| SBR Waste Solutions Limited | Water & waste | 2025 |
| SC Groundworks Ltd | Construction | 2010 |
| SC4 (UK) Limited | Manufacturing | 2010 |
| Scalinis Scunthorpe Limited | Hospitality | 2019 |
| Scarpway Limited | Financial services | 1984 |
| Scent Reserve Ltd | Wholesale & retail | 2022 |
| SCM Transport Ltd Ltd | Transport & logistics | 2025 |
| SCM Way Ltd | Transport & logistics | 2024 |
| Scmg Properties Limited | Real estate | 2023 |
| Scott Lane Bawtry Limited | Real estate | 2021 |
| Scott's Meats (Scunthorpe) Ltd | Wholesale & retail | 1985 |
| Scotton Construction Limited | Construction | 2004 |
| Scotty's Independent Trading Ltd | Wholesale & retail | 2024 |
| Scout Transport Ltd | Transport & logistics | 2018 |
| Sculpted by Shauni Ltd | Health & social care | 2025 |
| Scunny Barbers Ltd | Other services | 2021 |
| Scunny Estera Store Ltd | Wholesale & retail | 2024 |
| Scunny Hagar Ltd | Wholesale & retail | 2024 |
| Scunny Hand Car Wash Ltd | Administrative & support | 2024 |
| Scunny Local Ltd | Wholesale & retail | 2025 |
| Scunny Local Store Ltd | Wholesale & retail | 2023 |
| Scunny Pound Plus Limited | Wholesale & retail | 2025 |
| Scunnyformwork and Civils Ltd | Construction | 2020 |
| Scunthorpe Air Conditioning Ltd | Construction | 2026 |
| Scunthorpe and District Citizens Advice Bureau | Other services | 2005 |
| Scunthorpe and District Motor Sport Club Limited | Arts & recreation | 2005 |
| Scunthorpe and North Lincolnshire Community Radio CIC | Information & communication | 2020 |
| Scunthorpe Audio Ltd | Wholesale & retail | 2026 |