| Styled Home Studios Ltd | Professional & scientific | 2021 |
| Subterranean Light Limited | Professional & scientific | 2021 |
| Suburban Services Limited | Transport & logistics | 2025 |
| SUE Hobden Consulting Ltd | Professional & scientific | 2016 |
| SUE Mcgorian Legal Services Limited | Professional & scientific | 2020 |
| SUE Sherrard Consulting Limited | Professional & scientific | 2025 |
| Suire Marine and Industrial Engineering Services Limited | Manufacturing | 2016 |
| Sukumasup Ltd | Education | 2026 |
| SUM Finance Limited | Professional & scientific | 2013 |
| Summerhill Chestnuts Limited | Households | 1986 |
| Summerhill Grange Residents Management Company Limited | Households | 2021 |
| Summit Business Support Services Ltd | Administrative & support | 2015 |
| Summit Health & Safety Management Limited | Administrative & support | 2009 |
| Sunninghill Construction Trustees Limited | Professional & scientific | 2025 |
| Sunninghill Holdings Limited | Financial services | 2024 |
| Sunninghill Properties Limited | Construction | 1963 |
| Sunrise Films Limited | Information & communication | 2015 |
| Sunset Design Limited | Information & communication | 2014 |
| Supercar Golf Tours Ltd | Administrative & support | 2022 |
| Supermax Partners Limited | Information & communication | 2020 |
| Supershow Limited | Information & communication | 1981 |
| Support Team Group Limited | Information & communication | 2004 |
| Surah's PUB & Dining Limited | Hospitality | 2023 |
| Surgenet Ltd | Wholesale & retail | 2021 |
| Suroboruo Limited | Professional & scientific | 2007 |
| Surrey Auto Care Limited | Extraterritorial | 2013 |
| Surrey Bespoke Doors Ltd | Manufacturing | 2025 |
| Susan Clark Consultancy Limited | Professional & scientific | 2009 |
| Sussex Airport Transfers Limited | Transport & logistics | 2019 |
| Sussex and South Mortgages Ltd | Financial services | 2026 |
| Sussex Chocolates Ltd | Hospitality | 2024 |
| Sussex Cocktail Bars Ltd | Hospitality | 2015 |
| Sussex Coffee Trucks Ltd | Hospitality | 2020 |
| Sussex Contemporary Ltd | Administrative & support | 2022 |
| Sussex Dual Control Cars Limited | Administrative & support | 2010 |
| Sussex Ecohomes Ltd | Construction | 2025 |
| Sussex Endocrinology Limited | Health & social care | 2018 |
| Sussex Energy Centre Limited | Professional & scientific | 2007 |
| Sussex Equestrian Sales Limited | Agriculture & fishing | 2014 |
| Sussex Family Funeral Directors Limited | Other services | 2014 |
| Sussex Finance Director Limited | Professional & scientific | 2023 |
| Sussex Fleet Maintenance Limited | Wholesale & retail | 2026 |
| Sussex Foot Care Centre Limited | Health & social care | 2018 |
| Sussex Gardens Trust | Other services | 1996 |
| Sussex High Weald Dairy Ltd | Manufacturing | 2016 |
| Sussex Home Developments Ltd | Construction | 2018 |
| Sussex Learning Trust | Education | 2011 |
| Sussex Lipofreeze Clinic Limited | Other services | 2019 |
| Sussex Maid Services Ltd | Administrative & support | 2019 |
| Sussex Marquees Limited | Administrative & support | 2010 |
| Sussex Miniature Locomotive Society Limited | Arts & recreation | 1975 |
| Sussex Neurophysiology Ltd | Health & social care | 2019 |
| Sussex Podcast Studio Limited | Information & communication | 2024 |
| Sussex Rural Services Limited | Agriculture & fishing | 2021 |
| Sussex Saunas Limited | Construction | 2026 |
| Sussex School Transport Limited | Transport & logistics | 2019 |
| Sussex Sports Massage Therapy Limited | Health & social care | 2014 |
| Sussex Sports Turf Ltd | Arts & recreation | 2024 |
| Sussex Stabilisation Group Limited | Construction | 2019 |
| Sussex Sugarcraft LLP | | 2015 |
| Sussex Swimming Academy Ltd | Education | 2026 |
| Sussex Tech Support Ltd | Information & communication | 2022 |
| Sussex Tuition Centre Ltd | Education | 2017 |
| Sussex Ultrasound Services Ltd | Health & social care | 2006 |
| Sussex Venture Partners Limited | Extraterritorial | 2022 |
| Sussex Wealth Management Limited | Financial services | 2012 |
| Sustain Systems Limited | Information & communication | 2003 |
| Sustainability Analytics Ltd | Information & communication | 2017 |
| Sustainable Impact Limited | Construction | 2015 |
| SW Auto Repairs Ltd | Wholesale & retail | 2006 |
| Swallowfields Management Company Limited | Other services | 1995 |
| Swan Press Limited | Manufacturing | 1998 |
| Sweeptech Environmental Services Ltd | Other services | 2013 |
| Sweeptech North East Ltd | Other services | 2024 |
| Sweeptech North West Ltd | Other services | 2024 |
| Sweeptech Yorkshire Ltd | Other services | 2024 |
| Swift Personal Training Ltd | Arts & recreation | 2020 |
| Swim Good Limited | Wholesale & retail | 2025 |
| Swimming Pool Renovation Company Limited | Construction | 2011 |
| Swish Swish Ltd | Administrative & support | 2019 |
| Swiss Capital Limited | Administrative & support | 2018 |
| Swiss Nutrition Ltd | Wholesale & retail | 2023 |
| Switch on Services Limited | Construction | 2007 |
| Swoodura Ltd | Real estate | 2021 |
| Swoove Fitness Community Interest Company | Arts & recreation | 2015 |
| Swym Gims Limited | Arts & recreation | 2012 |
| Sycamore Grove Developments Limited | Real estate | 2014 |
| Sydneyroad Limited | Households | 2011 |
| Sylco Labs Limited | Information & communication | 2025 |
| Symphonia Art CIC | Education | 2026 |
| Sync Events Limited | Information & communication | 2025 |
| Syncbox Limited | Administrative & support | 2009 |
| Synchromedia Limited | Information & communication | 1998 |
| Syncto Limited | Information & communication | 2015 |
| Synergy Projects Ltd | Construction | 2024 |
| T & H Robinson Ltd | Administrative & support | 2019 |
| T & T Gardening Services Ltd | Administrative & support | 2022 |
| T&R Media Consulting Ltd | Professional & scientific | 2018 |
| T. J. Blasting & Coatings Services Ltd. | Manufacturing | 2017 |
| T.E. O'Kane Limited | Administrative & support | 2022 |