| S&Z 2020 Limited | Construction | 2020 |
| S.A. Cuss Limited | Construction | 2007 |
| S.H. Medical Care Limited | Health & social care | 2021 |
| S.J.M. Eurostat (U.K.) Limited | Wholesale & retail | 1994 |
| S.L.P.Carpentry & Timber Frame Solutions Ltd | Construction | 2005 |
| S3 Sales Ltd | Administrative & support | 2012 |
| S4S Vehicle Logistics Ltd | Transport & logistics | 2018 |
| Sacco Beauty Ltd | Other services | 2017 |
| Saddle Seller Limited | Wholesale & retail | 2019 |
| Safari Drive Limited | Administrative & support | 1993 |
| Safebuild Solutions Limited | Professional & scientific | 2025 |
| SAFEHANDSCARE24-7 Ltd | Health & social care | 2023 |
| Safehaven CLG Ltd | Information & communication | 2026 |
| Saffin Trading Ltd | Wholesale & retail | 2023 |
| SAG Guttering Ltd | Construction | 2022 |
| Saiger Engineering Services Limited | Professional & scientific | 2011 |
| Saku Mind Ltd | Information & communication | 2020 |
| Saladin Investment Limited | Real estate | 2012 |
| Sally Tankard Limited | Professional & scientific | 2022 |
| Sally's Signs Limited | Other services | 2012 |
| Salon Secrets Limited | Professional & scientific | 2008 |
| Saltas Hebden Ltd | Wholesale & retail | 2025 |
| Salts Hairdressing and Barbering Ltd | Other services | 2022 |
| Samantha Francome Ltd | Other services | 2025 |
| Samara Equine Ltd | Agriculture & fishing | 2025 |
| Samarkand Technical Ltd | Manufacturing | 2025 |
| Samco UK Limited | Construction | 2008 |
| Sams Solutions Wiltshire Limited | Construction | 2025 |
| Sand Buchanan Ltd | Manufacturing | 2018 |
| Sandbrooks Services Ltd | Health & social care | 2025 |
| Sanderson Aldridge Valuations Limited | Administrative & support | 2005 |
| Sandlea Associates Limited | Administrative & support | 2011 |
| Sandlea Developments Limited | Real estate | 2026 |
| Sandpiper Group Holdings Limited | Professional & scientific | 2025 |
| Sandpiper Group Property Limited | Real estate | 2025 |
| Sandplay, Creative Arts & Trauma Training Limited | Health & social care | 2013 |
| Santorini Food Ltd | Hospitality | 2025 |
| SAP Enabled NOW Ltd. | Information & communication | 2016 |
| Sapphire Foods Limited | Wholesale & retail | 2012 |
| Sarah Bowen PR Limited | Professional & scientific | 2025 |
| Sarah Currie Limited | Information & communication | 2008 |
| Sarah Hall Financial Planning Limited | Financial services | 2025 |
| Sarah Latham Limited | Professional & scientific | 2006 |
| Sarluso Ltd | Administrative & support | 2001 |
| Sarsen Games Ltd | Other services | 2021 |
| Sarsen Holdings Limited | Real estate | 2015 |
| SAT-7 Ltd | Professional & scientific | 2025 |
| SAT-7 UK Trust Limited | Other services | 1997 |
| Satchell Transport Ltd | Transport & logistics | 2003 |
| Sathvi & Sathu Ltd | Real estate | 2021 |
| Sathvi Ltd | Wholesale & retail | 2020 |
| SAW Aviation Limited | Education | 2022 |
| Saxon Laminates Limited | Administrative & support | 2006 |
| Sbig Holdings Ltd | Financial services | 2020 |
| Scaler Ventures Ltd | Information & communication | 2025 |
| Scattyzebra Ltd | Other services | 2023 |
| Scean Homes Ltd | Construction | 2021 |
| Scholar & Frank Ltd | Professional & scientific | 2020 |
| Scholars Chippenham Limited | Real estate | 2017 |
| Scholars Schoolwear Limited | Real estate | 1997 |
| Scholary Limited | Information & communication | 2013 |
| Scott Baxter Ltd | Manufacturing | 2019 |
| Scott Dunlop Interiors Limited | Construction | 2007 |
| Scott MAC Media Ltd | Professional & scientific | 2022 |
| Scott Windle Property Services Ltd | Real estate | 2021 |
| Scott.Emes-Contractors Ltd | Information & communication | 2023 |
| Scrawlrbox Ltd | Wholesale & retail | 2015 |
| SDN Logistics Ltd | Wholesale & retail | 2022 |
| Seabreeze Coaching Ltd | Professional & scientific | 2006 |
| Seager Publishing Limited | Information & communication | 1994 |
| Seagrove Consulting Limited | Professional & scientific | 2000 |
| Seagry Consultancy Ltd | Professional & scientific | 2018 |
| Seagry Cyber Ltd | Information & communication | 2024 |
| Seanda Limited | Professional & scientific | 2022 |
| Security One Step Ltd | Administrative & support | 2026 |
| Security Watch Limited | Administrative & support | 2017 |
| Security Wizardry Limited | Information & communication | 2006 |
| Seen & Herb Ltd | Wholesale & retail | 2025 |
| Select Medical Services Limited | Professional & scientific | 2003 |
| Selectiv-I Ltd | Administrative & support | 2019 |
| Selfix Builders Ltd | Construction | 2022 |
| Selwoodrj Ltd | Professional & scientific | 2023 |
| SEN Action Limited | Professional & scientific | 2015 |
| Sendfall Limited | Hospitality | 2006 |
| Sensible Consulting Ltd | Professional & scientific | 2025 |
| Sequel Properties Ltd | Manufacturing | 1994 |
| Sequoia Insights Limited | Information & communication | 2023 |
| SET Pro Automation Limited | Information & communication | 2014 |
| SEVEN3 Bespoke Works Limited | Construction | 2021 |
| Severells Fields Developers Ltd | Real estate | 2020 |
| SEW Divine Ltd | Other services | 2025 |
| SF Planning Link Limited | Administrative & support | 2007 |
| SFC Home Improvements Limited | Construction | 2006 |
| Sgates Motors Ltd | Wholesale & retail | 2024 |
| Shardrich PT Company Limited | Extraterritorial | 2023 |
| Shaw Renewable Links Limited | Transport & logistics | 2017 |
| Shbs Wiltshire Limited | Construction | 2016 |
| Shear Class Salon Limited | Administrative & support | 2006 |
| Shed Cider Ltd | Extraterritorial | 2015 |
| Sheldon Business Park Limited | Administrative & support | 1998 |