| Suntrap Investments Ltd | Financial services | 2025 |
| Super Scaffolding Services Limited | Construction | 2024 |
| Supersmile Care Limited | Health & social care | 2017 |
| Superstop Limited | Wholesale & retail | 2022 |
| Supplementheroes Limited | Manufacturing | 2025 |
| Supply Support Ltd | Administrative & support | 2022 |
| Supporting Spaces Limited | Construction | 2021 |
| Supreme Heating and Plumbing Services Limited | Construction | 2023 |
| Supreme Properties 369 Ltd | Real estate | 2021 |
| Sure Power Ltd | Energy | 2020 |
| SURGERY@102 Limited | Health & social care | 2010 |
| Surrey Dental Care Limited | Health & social care | 2008 |
| Susan Bellwo Limited | Wholesale & retail | 2019 |
| Susans Mews Eastbourne Management Limited | Real estate | 2025 |
| Sussex Aggregate Supplies Limited | Wholesale & retail | 2019 |
| Sussex Armoury Limited | Wholesale & retail | 1983 |
| Sussex Automotive Services Limited | Wholesale & retail | 2024 |
| Sussex Base Works Ltd | Construction | 2018 |
| Sussex Build Projects Ltd | Administrative & support | 2012 |
| Sussex Business Consulting Ltd | Professional & scientific | 2014 |
| Sussex Cardiology Ltd | Health & social care | 2024 |
| Sussex Cars (Eastbourne) Limited | Transport & logistics | 2014 |
| Sussex Cars Limited | Other services | 2023 |
| Sussex Children's Care Ltd | Health & social care | 2020 |
| Sussex Clean Ltd | Administrative & support | 2025 |
| Sussex Coast Pubs Limited | Hospitality | 2024 |
| Sussex Commercial Cleaning Ltd | Administrative & support | 2022 |
| Sussex Energy Advisors Ltd | Other services | 2013 |
| Sussex Equine Assisted Learning Ltd | Education | 2024 |
| Sussex Family Funeral Services Limited | Other services | 2022 |
| Sussex Fine Art Company Ltd | Wholesale & retail | 2019 |
| Sussex Fire Ltd | Administrative & support | 2026 |
| Sussex Fitted Furniture Ltd | Construction | 2025 |
| Sussex Flash Clean Ltd | Administrative & support | 2025 |
| Sussex Flooring Ltd | Wholesale & retail | 2025 |
| Sussex Ground Designs Limited | Construction | 2012 |
| Sussex Guildhall CIC | Education | 2025 |
| Sussex Gynaecology Services Ltd | Health & social care | 2023 |
| Sussex Health Hub Ltd | Health & social care | 2026 |
| Sussex Healthcare Solutions Ltd | Health & social care | 2020 |
| Sussex Immigration Services Limited | Professional & scientific | 2025 |
| Sussex Installation Team Limited | Manufacturing | 2008 |
| Sussex Iron Craft (South Eastern) Limited | Manufacturing | 1972 |
| Sussex Landscaping Ltd | Administrative & support | 2017 |
| Sussex Legal Consultants Limited | Professional & scientific | 2016 |
| Sussex Logs, Landscaping & Forestry Ltd | Agriculture & fishing | 2022 |
| Sussex MAN and a Van Ltd | Transport & logistics | 2019 |
| Sussex Media Ltd | Professional & scientific | 2020 |
| Sussex Medical Care Limited | Health & social care | 2021 |
| Sussex Mental Health Training Limited | Other services | 2025 |
| Sussex Nightstop Plus Limited | Health & social care | 2009 |
| Sussex Patios and Brickwork Ltd | Construction | 2023 |
| Sussex Products Ltd | Administrative & support | 2016 |
| Sussex Property Doctor Ltd | Construction | 2023 |
| Sussex Property Group Ltd | Manufacturing | 2019 |
| Sussex Property Investments Ltd | Construction | 2026 |
| Sussex Resomation Limited | Other services | 2022 |
| Sussex Sofas Ltd | Wholesale & retail | 2025 |
| Sussex Stores Ltd | Wholesale & retail | 2020 |
| Sussex Swim Life Ltd | Education | 2025 |
| Sussex Tandoori Ltd | Hospitality | 2018 |
| Sussex Taxis Limited | Transport & logistics | 1997 |
| Sussex Teachers Limited | Administrative & support | 2013 |
| Sussex Trade Ltd | Wholesale & retail | 2023 |
| Sussex Vascular Solutions Limited | Health & social care | 2010 |
| Sussex Ventilation Services Limited | Professional & scientific | 2025 |
| Sussex Wedding Photography Ltd. | Professional & scientific | 2016 |
| Sustained Change Limited | Information & communication | 2016 |
| SUX Ltd | Information & communication | 2021 |
| Swan Business Centre Hailsham Limited | Real estate | 2016 |
| Swan Mews Limited | Real estate | 2018 |
| Swapwise Limited | Wholesale & retail | 2025 |
| Sweet and Toys Shop Ltd | Wholesale & retail | 2025 |
| Sweet Circus CIC | Wholesale & retail | 2019 |
| Swell Force Consulting Ltd | Information & communication | 2022 |
| Swell Revolution | Arts & recreation | 2020 |
| Swhite Consultancy Ltd | Professional & scientific | 2025 |
| Swiftaccess Auto Ltd | Extraterritorial | 2025 |
| Switched on App Limited | Administrative & support | 2015 |
| Sws-Uk Ltd | Wholesale & retail | 2024 |
| SY Business Services Ltd | Financial services | 2025 |
| Syclick Holdings Limited | Professional & scientific | 2011 |
| Syclick Limited | Information & communication | 1999 |
| Sylveco Ltd | Wholesale & retail | 2021 |
| Symack Ltd | Real estate | 2009 |
| Symcar Consulting Limited | Information & communication | 2006 |
| Symes Consultancy Limited | Professional & scientific | 2022 |
| Synergy Software Solutions Ltd | Information & communication | 2018 |
| Synex Developments Ltd | Real estate | 2021 |
| Synth Palace Limited | Information & communication | 2025 |
| Syntheto Construction Limited | Construction | 2016 |
| Syntiq Ltd | Professional & scientific | 2023 |
| Systems Electric Testing Limited | Administrative & support | 2009 |
| Sysware Systems Limited | Information & communication | 2020 |
| SZQ Professional Services Ltd. | Construction | 2011 |
| T & C GAS Services Ltd | Construction | 2014 |
| T & Z Ellis Ltd | Health & social care | 2024 |
| T a Design Limited | Professional & scientific | 2002 |
| T and M Fireplaces Ltd | Construction | 2023 |
| T G Williamson Holdings Ltd | Real estate | 2024 |