| Skyewood Property Ltd | Real estate | 2024 |
| SL Energy Ltd | Construction | 2023 |
| SLB Construction Limited | Construction | 2018 |
| Small Giraffe Productions Ltd | Information & communication | 2019 |
| SMH BD Limited | Hospitality | 2026 |
| Smile Logisticss Ltd | Transport & logistics | 2020 |
| SMK International Ltd | Administrative & support | 2022 |
| SMR GAS and OIL Limited | Construction | 2003 |
| Smythe Gardens Management Company Limited | Households | 2016 |
| Snooks Farm Limited | Real estate | 2021 |
| Soco Ltd | Information & communication | 2019 |
| Sole Solutions Limited | Professional & scientific | 2012 |
| Solent Agricultural Services Ltd | Agriculture & fishing | 2023 |
| Solent Brands Limited | Other services | 2016 |
| Solent Check Limited | Professional & scientific | 2026 |
| Solent Deli Ltd | Wholesale & retail | 2021 |
| Solent Events Limited | Transport & logistics | 2004 |
| Solent Geo-Consultants Limited | Extraterritorial | 2013 |
| Solent Global Holdings Limited | Financial services | 2013 |
| Solent Global Limited | Financial services | 2017 |
| Solent Health Group Limited | Health & social care | 2020 |
| Solent Homecare Limited | Wholesale & retail | 2015 |
| Solent International Limited | Wholesale & retail | 2001 |
| Solent Marine Parts Ltd | Wholesale & retail | 2019 |
| Solent Packaging Limited | Wholesale & retail | 2003 |
| Solent Reach Farm Ltd | Real estate | 2016 |
| Solent RIB Charters Limited | Transport & logistics | 2001 |
| Solent RIB Hire Limited | Extraterritorial | 2006 |
| Solent Splicing Ltd | Extraterritorial | 2021 |
| Solent Therapeutic Services Limited | Health & social care | 2016 |
| Solent Yacht Care Limited | Administrative & support | 2011 |
| Solent Yachts Ltd | Wholesale & retail | 2007 |
| Solicitors Ltd | Information & communication | 2008 |
| Solo Offshore Racing Club Limited | Arts & recreation | 2004 |
| Solutions Water and Air Management Limited | Water & waste | 1999 |
| Solvecourt Services Limited | Construction | 1993 |
| Solwat Green Energy Ltd | Construction | 2020 |
| Solwat Green Maintenance Ltd | Professional & scientific | 2025 |
| Sophie Lets Ltd | Real estate | 2019 |
| Sophie's Pet Care Limited | Other services | 2014 |
| SOS Records Ltd | Information & communication | 2026 |
| Sound Factory Mobile Disco and Karaoke Ltd | Arts & recreation | 2025 |
| Sound Futures Ltd | Education | 2012 |
| Soundtribe Ltd | Wholesale & retail | 2025 |
| Source Group Limited | Professional & scientific | 1989 |
| Source Limited | Professional & scientific | 1987 |
| Source Premium and Promotional Consultants Limited | Professional & scientific | 1987 |
| South Coast Contracting & Developments Limited | Construction | 2016 |
| South Coast Detailing Ltd | Wholesale & retail | 2022 |
| South Coast Dyslexia Limited | Education | 2025 |
| South Coast EAR Care Ltd | Health & social care | 2025 |
| South Coast Marquees Limited | Administrative & support | 2005 |
| South Grove Maintenance (Lymington) Limited | Households | 1984 |
| South Grove Management Company Limited | Households | 2009 |
| South Street Pennington Management Company Limited | Real estate | 2015 |
| Southampton Rental Properties Ltd | Real estate | 2018 |
| Southampton Transport Services Ltd | Transport & logistics | 2018 |
| Southern Rentals Ltd | Administrative & support | 2026 |
| Southern Stationery Limited | Wholesale & retail | 2015 |
| Southsea Ventures Limited | Transport & logistics | 2010 |
| Southwater Residents Association Limited | Households | 1965 |
| SOW Fresh Limited | Wholesale & retail | 2020 |
| Space Dynamics Ltd | Professional & scientific | 2023 |
| Space Vision Limited | Professional & scientific | 1999 |
| Space@Lymington Ltd | Real estate | 2019 |
| Spartan Loft and Roof Conversions Ltd | Construction | 2025 |
| Specialist HR Solutions Limited | Professional & scientific | 2013 |
| Spectrum Geomatics Limited | Professional & scientific | 2017 |
| Spectrum Geophysics Limited | Professional & scientific | 2016 |
| Spectrum Geosurvey Limited | Professional & scientific | 2013 |
| Spectrum Offshore Limited | Professional & scientific | 2013 |
| Spectrum Vessel Services Limited | Transport & logistics | 2014 |
| Spook Days Limited | Administrative & support | 2015 |
| Spring Green London Limited | Manufacturing | 2016 |
| Springbok Investments Limited | Real estate | 2008 |
| Springbourne Property Limited | Real estate | 2018 |
| Springhill Haulage Ltd | Transport & logistics | 2018 |
| Springtide Accountancy Limited | Professional & scientific | 2002 |
| Squirrel Worx Ltd | Professional & scientific | 2023 |
| SRC Combined Holdings Ltd | Extraterritorial | 2022 |
| ST Barbe Museum and Art Gallery | Arts & recreation | 1993 |
| ST Thomas Park RTM Company Limited | Households | 2022 |
| ST Thomas Training Ltd | Education | 2014 |
| ST. George's Hospital Limited | Health & social care | 1980 |
| Stacey Edwards Dance Limited | Education | 2016 |
| Standley Estates Limited | Professional & scientific | 2014 |
| Standley Investments and Developments Limited | Construction | 2024 |
| Standley Investments Limited | Real estate | 2025 |
| Standley Property Limited | Real estate | 2003 |
| Stanwells Limited | Wholesale & retail | 1999 |
| Starboard Engineering Ltd | Manufacturing | 2021 |
| Startsort Limited | Real estate | 1989 |
| Steadhurst Limited | Hospitality | 2001 |
| Steadman Lloyd Construction Ltd | Construction | 2016 |
| Steadman-Lloyd Group Limited | Construction | 2013 |
| Stealth Holdings (Hampshire) Limited | Construction | 2016 |
| Stecco Limited | Construction | 2018 |
| Stevens & Co Ltd | Information & communication | 2013 |
| Still Waters Consultancy Services Ltd | Professional & scientific | 2021 |
| Stone & Co Financial Advisers Limited | Financial services | 2024 |