| SE2 Limited | Professional & scientific | 2004 |
| Seasons Eatings Ltd | Hospitality | 2024 |
| Second Wound Films Ltd | Arts & recreation | 2026 |
| Secure Shield Solutions Limited | Administrative & support | 2024 |
| Security West (Frome) Limited | Administrative & support | 2011 |
| Selfscapes CIC | Education | 2025 |
| Selwood Academy | Education | 2011 |
| Selwood Road (Frome) Management Company Limited | Households | 1990 |
| Selwood Road RTM Company Ltd | Households | 2025 |
| SEN Rights Ltd | Professional & scientific | 2018 |
| Sensory Security Ltd | Extraterritorial | 2025 |
| Serendipity Labs Limited | Information & communication | 2025 |
| Serenity Beauty Dean Limited | Other services | 2012 |
| Serenità by Megan Ltd | Other services | 2025 |
| Serious Property Matters Ltd | Real estate | 2022 |
| Seven Summits Networking Limited | Information & communication | 2007 |
| Sevy's Sports Bar Ltd | Hospitality | 2015 |
| SG Communications Ltd | Information & communication | 2024 |
| Sharp Design Services Limited | Professional & scientific | 2017 |
| Shearwater Analytics Ltd | Professional & scientific | 2022 |
| Shed Editorial Limited | Information & communication | 2016 |
| Shepton Mallet Arts and Culture CIC | Education | 2019 |
| Sherlock Residence Limited | Health & social care | 2018 |
| Shift Bristol Community Interest Company | Education | 2010 |
| Shiner Accountancy Limited | Professional & scientific | 2003 |
| Shining Limited | Information & communication | 2002 |
| Shop Assembly Limited | Wholesale & retail | 2015 |
| Shop Hidden Treasure Limited | Wholesale & retail | 2024 |
| Shouts.Gg Ltd | Information & communication | 2025 |
| Showsmiths Ltd | Arts & recreation | 2015 |
| Showsound Limited | Arts & recreation | 2000 |
| Sightline Connect Limited | Professional & scientific | 2026 |
| Silken Favours Limited | Wholesale & retail | 2010 |
| Simon Baker Design Limited | Other services | 2018 |
| Sine-Post Audio Ltd | Information & communication | 2016 |
| Singularity Systems Limited | Information & communication | 2014 |
| Sinners Music Limited | Wholesale & retail | 2012 |
| Sires Solar (Abbey Mill) Ltd | Energy | 2026 |
| SIX Films Ltd | Information & communication | 2023 |
| Skillman Accountancy Limited | Professional & scientific | 2013 |
| Skills Provision Limited | Administrative & support | 2007 |
| Skull and Dagger Limited | Other services | 2023 |
| Skye Surfacing Limited | Construction | 2014 |
| SL Edwards Services Limited | Other services | 2022 |
| Sleemans Q & C Ltd | Administrative & support | 2018 |
| Sleeple Ltd | Education | 2023 |
| Sleepsenseinternational Ltd | Wholesale & retail | 2021 |
| Slindon Ltd | Agriculture & fishing | 2023 |
| Slocombe Poole Properties Limited | Construction | 2017 |
| Sloe Works Ltd | Wholesale & retail | 2024 |
| Smart Growth Analytics Ltd | Professional & scientific | 2011 |
| Smee ID Limited | Professional & scientific | 2024 |
| Snapsavvy Limited | Professional & scientific | 2025 |
| Snelling Construction Ltd | Construction | 2021 |
| SO Accounting Limited | Professional & scientific | 2019 |
| SOB Haulage Ltd | Administrative & support | 2020 |
| Sodapop Software Ltd | Information & communication | 2024 |
| Solas Services International Limited | Other services | 2022 |
| Solomon and Friends Dog Daycare Ltd | Other services | 2025 |
| Somer Industries Limited | Manufacturing | 2022 |
| Somerset Building & Preservation Limited | Construction | 2013 |
| Somerset Golf Club Limited | Arts & recreation | 2009 |
| Somerset Lavender Limited | Administrative & support | 2004 |
| Somerset Milk Ltd | Wholesale & retail | 2024 |
| Somerset Tribe CIC | Education | 2026 |
| Somersound Event Solutions Ltd | Manufacturing | 2024 |
| Sophie's Gardens Limited | Administrative & support | 2015 |
| Sorbus International Limited | Administrative & support | 2007 |
| Sorbus International Property Company Ltd | Real estate | 2023 |
| Sound Culture Audio Ltd | Manufacturing | 2022 |
| Sound Foundation Community Care | Other services | 2015 |
| Sourceglobal Limited | Professional & scientific | 1990 |
| South and West Plumbing & Heating Limited | Construction | 2011 |
| South Pizza Group Ltd | Hospitality | 2025 |
| South Wessex Community Rail Partnership C.I.C. | Transport & logistics | 2021 |
| South West Electric Gates Ltd | Construction | 2020 |
| South West Lighting Limited | Wholesale & retail | 2010 |
| South West Marquees Limited | Administrative & support | 1999 |
| South West Stables and Shelters Limited | Construction | 2015 |
| Southern Bells Ltd | Hospitality | 2020 |
| Southmoor Home Team Limited | Wholesale & retail | 2014 |
| Southwest Brickwork Limited | Construction | 2024 |
| SP Engineering Motorcycle Exhaust & Accessories Limited | Manufacturing | 2011 |
| Sparkling Invest Ltd | Agriculture & fishing | 2020 |
| Sparkling River Properties Limited | Real estate | 2018 |
| Sparktech Software Ltd | Information & communication | 2018 |
| Speakeasy Support Limited | Health & social care | 2010 |
| Special Stock 1992 Limited | Real estate | 1996 |
| Spencer's Caravan Services Ltd | Manufacturing | 2024 |
| Spinnaker Performance Psychology Ltd | Professional & scientific | 2023 |
| SPK Automation Ltd | Professional & scientific | 2016 |
| Splinter Structures Ltd | Professional & scientific | 2023 |
| Spop Limited | Real estate | 2012 |
| Sprake Commercial Properties Ltd | Financial services | 2024 |
| Sprake Properties Ltd | Real estate | 2021 |
| Spray Refinishing Ltd | Wholesale & retail | 2024 |
| Square Base Properties Ltd | Real estate | 2019 |
| Squareleg Promotions Ltd | Wholesale & retail | 2016 |
| Squires Acquisitions Ltd | Construction | 2015 |
| SRG Carpentry Ltd | Construction | 2015 |