| SAS Finishings Limited | Construction | 2023 |
| Sass Bars Limited | Hospitality | 2019 |
| Sauer & Oonk Adviseurs & Notarissen LLP | | 2017 |
| Saul Kidston & Sons Ltd | Transport & logistics | 2020 |
| Saule Ltd | Wholesale & retail | 2025 |
| Saunders Properties (SW) Limited | Real estate | 2020 |
| Save the Orangutan | Arts & recreation | 2009 |
| Savile Lloyd Limited | Administrative & support | 2007 |
| Savoy Court (Shaftesbury) Limited | Households | 1986 |
| Saxon Fencing Ltd | Construction | 2014 |
| Saxon Fields (Middlezoy) Management Company Limited | Households | 2024 |
| SB Accountancy and Bookkeeping Limited | Professional & scientific | 2014 |
| SB VET Locums Ltd | Professional & scientific | 2025 |
| Sbartlett Ltd | Financial services | 2026 |
| SBC Consulting and Engineering Ltd | Professional & scientific | 2019 |
| Sbfts Ltd | Wholesale & retail | 2020 |
| SC and HC Rogers Limited | Financial services | 2021 |
| Scale Engineering Ltd | Manufacturing | 2016 |
| Scaninvent Limited | Other services | 2005 |
| Scantron Industrial Products Limited | Professional & scientific | 1972 |
| Scantron Limited | Extraterritorial | 2005 |
| Scarborough Holdings Limited | Financial services | 2024 |
| Scarily Good Pubs Ltd | Hospitality | 2021 |
| Sccez Limited | Health & social care | 2025 |
| Sccollins FM Consultant Ltd | Professional & scientific | 2020 |
| Schaefer Financial Management Limited | Financial services | 2002 |
| Schulting & Partners LLP | | 2013 |
| SCI (ST Cross Interiors) Limited | Construction | 2020 |
| Science for Pets Ltd | Professional & scientific | 2025 |
| Science Unlimited C.I.C. | Education | 2018 |
| Scirocco Consultancy Limited | Professional & scientific | 2022 |
| Sclater Equine Ltd | Professional & scientific | 2011 |
| SCM Handling Limited | Manufacturing | 2002 |
| SCM Holdings Limited | Financial services | 2003 |
| SCM Materials Handling Limited | Professional & scientific | 2003 |
| Scoop and Go Ltd | Water & waste | 2025 |
| Scorpio Connect Limited | Wholesale & retail | 2002 |
| Scotia Hydrogen Ltd | Energy | 2020 |
| Scotsgrove Holdings Limited | Real estate | 1967 |
| Scott Aircraft Maintenance Limited | Professional & scientific | 2017 |
| Scott Mcgowan Roofing Limited | Construction | 2018 |
| Scott-Bates & Coles Ltd. | Real estate | 2009 |
| Scriptony Foundation Ltd | Information & communication | 2025 |
| Scrumpleton Ltd | Financial services | 2022 |
| Scuba Scene Limited | Arts & recreation | 2005 |
| Sculpture Events Factory International Limited | Extraterritorial | 2005 |
| Scwills Properties Ltd | Real estate | 2025 |
| SD Retail Group Ltd | Wholesale & retail | 2024 |
| SDC Property Ltd | Real estate | 2020 |
| SDM Consultancy (Essex) Limited | Professional & scientific | 2017 |
| SDS Holdings Limited | Financial services | 2008 |
| SDS Pipe Systems (Holdings) Limited | Financial services | 2019 |
| SDS Pipe Systems Limited | Manufacturing | 1986 |
| SDS Water Group Limited | Financial services | 2023 |
| Sea Bass Fish and Chips Limited | Hospitality | 2019 |
| SEA2SKY Management Solutions Limited | Professional & scientific | 2007 |
| Seaborough Garage Services Limited | Wholesale & retail | 2022 |
| Seagull Cottages Limited | Real estate | 2020 |
| Seaking Dude Ltd | Administrative & support | 2025 |
| Seala Holdings Limited | Construction | 2022 |
| SEB Photography Ltd | Manufacturing | 2025 |
| Sebina Ventures Limited | Financial services | 2007 |
| SEC Properties Limited | Real estate | 2007 |
| Seddon Cardiology Limited | Professional & scientific | 2019 |
| Sedulousco Ltd | Administrative & support | 2016 |
| Seefish Limited | Wholesale & retail | 2007 |
| SEF Cleaning Services Ltd | Administrative & support | 2022 |
| Sehion Taxi &Travels Ltd | Transport & logistics | 2024 |
| Selby Digital Ltd | Wholesale & retail | 2019 |
| Selcouth Stays Ltd | Hospitality | 2020 |
| Select Consultancy Solutions Ltd | Professional & scientific | 2014 |
| Select Denture Centre Limited | Manufacturing | 2001 |
| Select VAT Services Limited | Professional & scientific | 2024 |
| Selective Financial Services (Investment) Co. Limited | Professional & scientific | 1997 |
| Selene Accounting Limited | Professional & scientific | 2015 |
| Self-Pay Limited | Financial services | 2001 |
| Semara Family Investment Limited | Financial services | 2021 |
| SEN DEN Somerset CIC | Education | 2024 |
| Send Group Ltd | Administrative & support | 2017 |
| Seneca Marine & Aerospace Ltd | Professional & scientific | 2025 |
| Sense Projects Ltd | Professional & scientific | 2019 |
| Sensory Connections Ltd | Health & social care | 2021 |
| Sentricore Ltd | Information & communication | 2026 |
| Serenadecapitalinc Limited | Information & communication | 2004 |
| Serendipity Creative Cafe Ltd | Arts & recreation | 2024 |
| Serenity Women's Clinic Limited | Health & social care | 2023 |
| Service Plus Home Care Ltd | Construction | 2019 |
| SES Saddlery Ltd | Manufacturing | 2016 |
| Sesta Grande Investments Limited | Financial services | 2021 |
| Seven Eighteen Limited | Professional & scientific | 2021 |
| Seven Pillars of Wisdom Limited | Education | 2017 |
| Seventh Rose Property Limited | Real estate | 2017 |
| Seville Court Management (Taunton) Limited | Households | 1978 |
| SEW What NOW Limited | Financial services | 2026 |
| Seya Cars Ltd | Wholesale & retail | 2025 |
| Seyton-Lister and Company Ltd | Financial services | 2017 |
| SFX Consultants Limited | Professional & scientific | 2019 |
| SG Brimacombe & Sons Limited | Agriculture & fishing | 2004 |
| SG Walsh Ltd | Health & social care | 2025 |
| SGC Consultancy Ltd | Professional & scientific | 2023 |