| Smarter Business Outcomes Ltd | Other services | 2014 |
| Smarter Practice Ltd | Information & communication | 2026 |
| SMB Designs Holdings Limited | Professional & scientific | 2019 |
| SMC Property Solutions Ltd | Construction | 2025 |
| SME Bristol Limited | Construction | 1999 |
| Smith & Mills Engineering Limited | Professional & scientific | 2018 |
| Smith Office Supplies Limited | Wholesale & retail | 2014 |
| Smithbrittain Ltd | Education | 2023 |
| Smokehouse BBQ Ltd | Hospitality | 2024 |
| Smokin Shadow Limited | Information & communication | 2009 |
| SMR Electronics Limited | Manufacturing | 2002 |
| SNC Maintenance Limited | Construction | 2010 |
| SNC Property Developments Limited | Construction | 2025 |
| SNJ Projects Limited | Professional & scientific | 2017 |
| Snook Design Limited | Information & communication | 2006 |
| Snow Associates (UK) Limited | Wholesale & retail | 2006 |
| Snowberry Nurseries Ltd | Financial services | 2024 |
| Snowdrop Cottage Day Nursery Limited | Health & social care | 2013 |
| Sofit Ltd | Arts & recreation | 2017 |
| Softcaw Limited | Information & communication | 2003 |
| Softstream Solutions Limited | Administrative & support | 2011 |
| Soko Digital Ltd | Professional & scientific | 2025 |
| Solarvolt Energy Ltd | Construction | 2024 |
| Somerdown Accountancy Services Limited | Professional & scientific | 2012 |
| Somerford House Limited | Real estate | 2013 |
| Somerford House Two Limited | Real estate | 2020 |
| Somerford Plumbing and Heating Limited | Construction | 2005 |
| Somerscott Construction Ltd | Construction | 2026 |
| Somerset School of Journalism Limited | Education | 2007 |
| Something Chic Ltd | Wholesale & retail | 2024 |
| Sonder Coffee & Events Ltd | Hospitality | 2025 |
| Sophie Turner Property Ltd | Real estate | 2016 |
| Sopworth Services Limited | Information & communication | 2001 |
| Sorellia Ltd | Other services | 2026 |
| Sosp Ltd | Information & communication | 2018 |
| Soteria Cyber and Digital Ltd | Information & communication | 2025 |
| South East Concrete Limited | Construction | 2007 |
| South West Clothing Co Limited | Wholesale & retail | 2021 |
| South West Commercial Cleaning Services Ltd | Administrative & support | 2023 |
| South West Control Systems Limited | Professional & scientific | 2008 |
| South West Home Care Ltd | Health & social care | 2018 |
| South West Piping Services Limited | | 1988 |
| South West Surveying Ltd | Professional & scientific | 2021 |
| South West Training Centre Ltd | Education | 2025 |
| Southbright Ltd | Other services | 2025 |
| Southern Academy of Sport Ltd | Health & social care | 2013 |
| Southern Counties Thatching Ltd | Construction | 2007 |
| Southern Healthcare Specialists Limited | Health & social care | 2014 |
| Sovereign Inns Ltd | Hospitality | 2023 |
| SP Madge and SON Ltd | Agriculture & fishing | 2026 |
| Sp-Project Management Services Ltd | Information & communication | 2011 |
| Space Tato Ltd | Information & communication | 2025 |
| Spaghetti Junction Limited | Construction | 1985 |
| Sparkling Sensations Ltd | Administrative & support | 2024 |
| Spartan International Security Limited | Administrative & support | 2017 |
| Spatial Fusion Technologies Ltd | Information & communication | 2025 |
| Spatialcortex Technology Limited | Professional & scientific | 2019 |
| Special Little Gift Co Ltd | Extraterritorial | 2021 |
| Specialist Engine Supplies Limited | Manufacturing | 2021 |
| Speedrange Limited | Administrative & support | 1986 |
| Spencer Whittle Design Limited | Construction | 2025 |
| Sphinx Consultants Limited | Information & communication | 1997 |
| Spice of Asia Lyneham Limited | Extraterritorial | 2006 |
| Spicer Safety Solutions Ltd | Professional & scientific | 2026 |
| Spiers Holdings Limited | Professional & scientific | 2019 |
| Spike Milligan Performance Horse Consultant Ltd | Professional & scientific | 2020 |
| Spinfield Solutions Limited | Administrative & support | 2009 |
| Spiritinspiredhealing Ltd | Other services | 2021 |
| Spiritual Light Limited | Financial services | 2013 |
| Sporting Group Limited | Wholesale & retail | 2023 |
| Sporting Leagues Limited | Arts & recreation | 2020 |
| Sporting Structures Ltd | Administrative & support | 2015 |
| Sporting-Gifts.Com Limited | Wholesale & retail | 1999 |
| Sports Ventures Ltd | Information & communication | 2023 |
| Spring CHE Limited | Energy | 2018 |
| Spring DEV 10 Limited | Energy | 2021 |
| Spring DEV 11 Limited | Energy | 2021 |
| Spring DEV 12 Limited | Energy | 2021 |
| Spring DEV 14 Limited | Energy | 2023 |
| Spring PR Limited | Administrative & support | 2006 |
| Springboard Chippenham | Health & social care | 1992 |
| Springleaze Project Management Ltd | Information & communication | 2014 |
| Spye Westbury Ltd | Information & communication | 2024 |
| SQI Electrical Services Limited | Construction | 2020 |
| Squeeky Cleaning Ltd | Administrative & support | 2025 |
| Squid Technology Limited | Wholesale & retail | 2005 |
| SR Dining Ltd | Hospitality | 2022 |
| Sscn Group Limited | Information & communication | 2026 |
| SSF Developments Ltd | Real estate | 2025 |
| SSQ Hall Committee Ltd | Real estate | 2014 |
| ST James's Square Bath Limited | Households | 2010 |
| ST Martins Consultancy Services Limited | Professional & scientific | 2008 |
| ST Martins Developments Limited | Construction | 2014 |
| Stafford Projects Limited | Professional & scientific | 2010 |
| Stancron Consultants Limited | Professional & scientific | 2022 |
| Stand by ME Standby Limited | Information & communication | 2012 |
| Stanhope PR Limited | Professional & scientific | 2002 |
| Stanton Ridge Limited | Financial services | 2025 |
| Star Property Maintenance Ltd | Households | 2014 |
| Starcairn Ltd | Professional & scientific | 2025 |