| Sculpture by the Lakes Limited | Arts & recreation | 2019 |
| Seacliff Court Management Company Limited | Households | 1999 |
| Secure Alarms Security Systems Limited | Administrative & support | 2001 |
| Select Interiors (Southern) Limited | Manufacturing | 2003 |
| Selmore Export Lines Limited | Professional & scientific | 1966 |
| Sensus Property Management & Services Limited | Real estate | 2003 |
| Serenity Beauty Limited | Wholesale & retail | 2001 |
| Setchfields Limited | Wholesale & retail | 1973 |
| Sevy Omaha Ltd | Health & social care | 2024 |
| Shaftesbury Abbey and Museum Preservation Trust Company Limited | Arts & recreation | 1985 |
| Shaftesbury Arts Centre | Arts & recreation | 2005 |
| Shaftesbury DRY Cleaners Limited | Other services | 1997 |
| Shanzey Dispense Ltd | Health & social care | 2026 |
| Sharief Ibrahim Limited | Health & social care | 2005 |
| Sharman Fencing Limited | Construction | 2005 |
| Shean & Hare Construction Ltd. | Construction | 2002 |
| Sheenroy Limited | | 1983 |
| Sherborne Curry Limited | Hospitality | 2022 |
| Sherwood House Management Company Ltd. | Administrative & support | 2003 |
| Shikdar Limited | Hospitality | 2006 |
| Shorequay Ltd | | 2007 |
| Shoreway of Weymouth Limited | Wholesale & retail | 1965 |
| Short Properties Limited | Real estate | 2007 |
| Shortwood House Management Limited | Households | 2005 |
| Sibbett Gregory Wright & Coles Ltd. | Real estate | 2000 |
| Sika Services Limited | Construction | 2006 |
| Silton Manor Limited | Wholesale & retail | 2001 |
| Silton Manor Properties Limited | Real estate | 2004 |
| Simon Gudgeon Sculpture Limited | Arts & recreation | 1998 |
| Simon Hartwell Limited | Wholesale & retail | 1978 |
| Simracing 4U Limited | Information & communication | 2004 |
| SL Telecom Limited | Extraterritorial | 2006 |
| Smisp Limited | | 1982 |
| Smith and Smith (Bridport) Limited | Wholesale & retail | 1955 |
| Smithtec Limited | Information & communication | 2005 |
| SMM Appledore Limited | Professional & scientific | 1963 |
| SMS Ventures Limited | Arts & recreation | 2005 |
| Snefru Limited | Information & communication | 1999 |
| Snugheat Ltd | Construction | 2007 |
| Softstay Limited | Real estate | 1989 |
| Software Centre Limited | Professional & scientific | 1990 |
| Solarna Limited | Hospitality | 2003 |
| Solarport Group Holdings Limited | Extraterritorial | 2022 |
| Solomax Limited | Water & waste | 1996 |
| Solos Power Ltd | Energy | 2020 |
| Solus Business Systems Limited | Wholesale & retail | 2001 |
| Somdor Engineering Limited | Manufacturing | 1975 |
| Somme Battlefield Tours Limited | Administrative & support | 1997 |
| South Coast Aviation (Bournemouth) Limited | Transport & logistics | 1997 |
| South Coast Publicity Limited | Professional & scientific | 2002 |
| Southcote Road Management Company (Bournemouth) Limited | Households | 1990 |
| Southern Electrical Services (UK) Ltd | Construction | 2005 |
| Southern Filters (Dorset) Ltd | Manufacturing | 2004 |
| Spacetodo Ltd | Information & communication | 2026 |
| Specialist Letting Agency Limited | Real estate | 2007 |
| Spill the Beans (Wimborne) Limited | Wholesale & retail | 2004 |
| Spinners Ltd | Administrative & support | 2005 |
| Spring Grove Forge Limited(The) | Manufacturing | 1950 |
| Sproston & Bowden Opticians Limited | Health & social care | 2003 |
| SSE Precision Engineering Limited | Manufacturing | 2004 |
| ST Albans Crescent Flat Management Limited | Real estate | 2007 |
| ST Giles Limited | Professional & scientific | 2002 |
| ST Gresham Limited | Professional & scientific | 2002 |
| ST Harding Limited | Real estate | 2006 |
| ST Manor Limited | Financial services | 2003 |
| ST Pauls Surveying Limited | Professional & scientific | 1994 |
| ST. Andrews Meadows Management Company Limited | Real estate | 1998 |
| ST. Cuthburga's Management Limited | Households | 1999 |
| ST. John's Close Management Company Limited | Households | 1981 |
| ST. Martins House Management Company (Wareham) Limited | Households | 1975 |
| Stable Mews (Sherborne) Management Company Limited | Households | 2022 |
| Stanborough (Construction) Limited | Construction | 1997 |
| Stanborough (Developments) Limited | Construction | 1971 |
| Stanton Garage Doors Limited | Construction | 2001 |
| Statue Kiosk Limited | Wholesale & retail | 2002 |
| Stemframe Limited | Construction | 1999 |
| Steppat Limited | Financial services | 2001 |
| Steve Hill Associates LLP | | 2002 |
| Stickley Civil Engineering Limited | Construction | 2003 |
| Stoke Water House Limited | Hospitality | 1972 |
| Stone Foundries Limited | Manufacturing | 1982 |
| Stone Manganese Marine Limited | Manufacturing | 2005 |
| Stoner and Shepherd Building Services LLP | | 2003 |
| Stour Motor Factors Limited | | 1978 |
| Stour Road Management Company Limited | Households | 2005 |
| Stratton Property Services Ltd | Real estate | 1999 |
| STS Lymington Limited | Financial services | 2006 |
| Stuart a MAY Ltd | Construction | 1997 |
| Stubeck Properties Limited | Real estate | 2008 |
| Students Residence Ltd | Extraterritorial | 2005 |
| Studio 401 Limited | Arts & recreation | 2002 |
| Sturminster Newton MOT Centre Limited | Wholesale & retail | 2001 |
| Sublime IT Solutions Ltd | Information & communication | 2015 |
| Sultan Irem Limited | Hospitality | 2023 |
| Sunbury Court(Bournmouth)Management Company Limited | Households | 1964 |
| Sunnyside Distribution Limited | Wholesale & retail | 1987 |
| Sunnyside Web Design Limited | Wholesale & retail | 2007 |
| Super Mare Scaffolding Limited | Construction | 1992 |
| Supportnet Technology Limited | Information & communication | 1999 |
| Surfheath Limited | Other services | 1991 |