| S106 Management Ltd | Administrative & support | 1997 |
| Safeharbour Support Limited | Information & communication | 2020 |
| Safetrek Limited | Professional & scientific | 2003 |
| Salaszoi Investments Limited | Financial services | 2023 |
| Salterton Associates Ltd | Administrative & support | 2020 |
| SAM Holden Limited | Professional & scientific | 2011 |
| Sampford Property Co Limited | Real estate | 2003 |
| Sancroft Homes Limited | Construction | 2023 |
| Sanders Studio Limited | Arts & recreation | 2010 |
| Sapience Cloud Ltd | Information & communication | 2022 |
| Sarah James Coaching and Consulting Ltd | Administrative & support | 2025 |
| Sawbridge Mills Management Company Ltd | Households | 2022 |
| Saxon-Jones Enterprises Ltd | Wholesale & retail | 2017 |
| Saychette Limited | Real estate | 1976 |
| SBJ Construction Limited | Construction | 2018 |
| SC Energy Solutions Limited | Professional & scientific | 2025 |
| SCB Property Investments Ltd | Real estate | 2025 |
| Scotia Knitting Company,Limited.(The) | Financial services | 1913 |
| Scott Brown Estates Ltd | Real estate | 2024 |
| Scotts Facilities Management Company Limited | Extraterritorial | 2007 |
| Scrub Daddy UK Ltd. | Wholesale & retail | 2013 |
| SE Watts Building Company Ltd | Construction | 2015 |
| Seaxburh Partners Ltd | Professional & scientific | 2017 |
| Second of MAY LLP | | 2012 |
| Sector Place Open Space Management Company Limited | Households | 2013 |
| Seddons Lettings Limited | Real estate | 2016 |
| Seen Properties Limited | Real estate | 2023 |
| Segrave Capital Management Ltd. | Financial services | 2023 |
| Sekular Limited | Administrative & support | 2026 |
| SELFSTORE24 Ltd | Transport & logistics | 2025 |
| Seven Crosses Limited | Professional & scientific | 2001 |
| Shallows Inc Limited | Health & social care | 2014 |
| Sharp Play Sports Limited | Arts & recreation | 2026 |
| Shelfstacker Ltd | Transport & logistics | 2025 |
| Sherborne Antiques Ltd | Wholesale & retail | 2017 |
| Shiroy Limited | Financial services | 2014 |
| Sics Gofal Cymru CYF | Education | 2011 |
| Signpost Magazine C.I.C. | Information & communication | 2018 |
| Silcombe Limited | Professional & scientific | 2026 |
| Silverton MVG 1 Limited | Real estate | 2017 |
| SIM Demon Ltd | Professional & scientific | 2019 |
| Sing Yourself Well CIC | Arts & recreation | 2024 |
| SIP Shed Ltd | Wholesale & retail | 2020 |
| SIX on Castle Ltd | Hospitality | 2022 |
| SJ & DM Diggle Electrical Limited | Construction | 2007 |
| SJ Reed (Agricultural Contractors ) Limited | Agriculture & fishing | 2015 |
| SJ Water Ltd | Water & waste | 2022 |
| Sj&N Associates Ltd | Professional & scientific | 2026 |
| Skdr Ltd | Wholesale & retail | 2025 |
| SKS Medical Consulting Limited | Health & social care | 2020 |
| SL Abode Ltd | Real estate | 2025 |
| Sliding Wardrobes South West Ltd | Manufacturing | 2008 |
| Small and Tidmas Limited | Manufacturing | 1948 |
| Small Farm Investments Limited | Agriculture & fishing | 2022 |
| Smart Drainage Ltd | Construction | 2019 |
| SOL Electrical Holdings Limited | Financial services | 2024 |
| SOL Electrical Limited | Construction | 2007 |
| Sole Trader Organisation Limited | Professional & scientific | 2013 |
| Solitec Engineering Limited | Manufacturing | 1998 |
| Sondavale Limited | Professional & scientific | 1976 |
| South West Air Tech Ltd | Construction | 2018 |
| South West Care Agency Limited | Administrative & support | 2022 |
| South West Combat Events Limited | Education | 2026 |
| South West Geotechnical Limited | Construction | 2002 |
| South West Plant Sales Limited | Wholesale & retail | 1998 |
| South West Secretarial Limited | Extraterritorial | 2004 |
| Southdown Meadows Boarding Kennels Ltd | Other services | 2025 |
| Southgate Properties (Stockwell) Ltd | Real estate | 2019 |
| Southill Stud Ltd | Agriculture & fishing | 2024 |
| Southlea Service Station Ltd | Wholesale & retail | 2006 |
| Southwestern Sustainability Limited | Energy | 2014 |
| Sovereign Counties Limited | Real estate | 1994 |
| Sovereign Partnership Ltd. | Wholesale & retail | 1996 |
| SOW HR Ltd | Administrative & support | 2026 |
| Spa Macro LLP | | 2025 |
| Spa Maroc LLP | | 2025 |
| Spades Gardens Ltd | Administrative & support | 2024 |
| Spark Consulting Services Limited | Health & social care | 2022 |
| Spec-Care Ltd | Other services | 2003 |
| Spend Badger Limited | Information & communication | 2025 |
| SPH Supplies Ltd | Wholesale & retail | 2012 |
| Spot on Decorating Services Limited | Construction | 2013 |
| Squid Inkorporated Ltd | Professional & scientific | 2015 |
| SR Hill Trading Limited | Construction | 2014 |
| SSC SW Ltd | Construction | 2025 |
| SSW Rural Ltd | Real estate | 2019 |
| ST Aubyn's Wood Property Management Company Limited | Households | 2012 |
| ST Aubyns Villas Management Limited | Real estate | 2017 |
| ST Charles Consulting Limited | Professional & scientific | 2014 |
| ST James' Court (Somerset) Management Limited | Real estate | 2015 |
| Stable Farm Management Company Limited | Hospitality | 1982 |
| Stablestone Law Ltd | Professional & scientific | 2018 |
| Stag Construction South West Limited | Construction | 2016 |
| Stag Woodland Ltd | Agriculture & fishing | 2023 |
| Staples VA Ltd | Administrative & support | 2023 |
| Stapp | Professional & scientific | 2023 |
| Star Connective Ltd | Administrative & support | 2025 |
| State of Emergency Limited | Arts & recreation | 1986 |
| State of Trust | Arts & recreation | 2014 |
| Staycaholidays Ltd | Hospitality | 2024 |