| RYE Restaurants Ltd | Hospitality | 2026 |
| RYE Wine Ltd | Wholesale & retail | 2022 |
| S & M Energy Consultancy Ltd | Professional & scientific | 2026 |
| S Rail Company Limited | Professional & scientific | 2019 |
| S&J Store Ltd | Wholesale & retail | 2025 |
| Saabtech (South East) Limited | Wholesale & retail | 2018 |
| Saftrans Europa Limited | Transport & logistics | 2020 |
| Sailing Starboard Ltd | Hospitality | 2019 |
| Saint Art Limited | Professional & scientific | 2009 |
| Saint Leonards Church Limited | Wholesale & retail | 2022 |
| Salisbury Court (Hove NO 2) Management Company Limited | Households | 2010 |
| Salisbury Court Hove (Freehold) Limited | Real estate | 2012 |
| Sally Georgina Group Ltd | Wholesale & retail | 2018 |
| Saltwater Sign Co Ltd | Manufacturing | 2025 |
| Samli Hair & Beauty Ltd | Other services | 2024 |
| Samsons Installations Limited | Construction | 2013 |
| Sands & Co Business Consultancy Limited | Professional & scientific | 2021 |
| Sanfi Ltd | Wholesale & retail | 2024 |
| Sariatli Ltd | Hospitality | 2023 |
| Saveonfashion Ltd | Wholesale & retail | 2018 |
| Savy Ltd | Professional & scientific | 2025 |
| SC Group Holdings Limited | Transport & logistics | 2017 |
| Scale Model Technical Services Limited | Manufacturing | 1998 |
| Scentfromaboveco Ltd | Wholesale & retail | 2025 |
| SCH Construction (Sussex) Limited | Construction | 2025 |
| Scotch Bonnet Productions Ltd | Information & communication | 2026 |
| Scott Garrett Ltd | Professional & scientific | 2013 |
| Script Consultancy Ltd | Information & communication | 2014 |
| SD Campbell Plumbing and Heating Engineers Limited | Construction | 2006 |
| SD Elite Limited | Administrative & support | 2013 |
| SD Rail Limited | Professional & scientific | 2016 |
| Sea Breeze Pilates Ltd | Arts & recreation | 2022 |
| Sea Kale Hastings Ltd | Hospitality | 2017 |
| Seaglass Arts Ltd. | Education | 2022 |
| Seagull House Freehold Limited | Households | 2021 |
| Seaport Learning Ltd | Administrative & support | 2022 |
| Seaview Close Residents Limited | Households | 2017 |
| Seaview Mansions RTM Company Limited | Households | 2020 |
| Sebastian Signs Limited | Arts & recreation | 2017 |
| Sebelli Healthcare Solutions Ltd | Health & social care | 2020 |
| Secure Care UK Limited | Transport & logistics | 2013 |
| Secure Care UK Trading Ltd | Health & social care | 2020 |
| Secure Stores Sussex Hailsham Limited | Transport & logistics | 2021 |
| Secureness-Shop Ltd. | Wholesale & retail | 2017 |
| Sehv Services Limited | Manufacturing | 2019 |
| Self-Pack to Self-Storage Limited | Transport & logistics | 2025 |
| Selva Hill Bobees Fried Chicken Ltd | Hospitality | 2024 |
| Semper Media Limited | Professional & scientific | 2012 |
| Semper Prorsum Ltd | Financial services | 2023 |
| Sentry Hosting Limited | Information & communication | 2025 |
| Serenity Projects (SE) Ltd | Construction | 2024 |
| Seventies Limited | Wholesale & retail | 2000 |
| Seventy Nine Marina Limited | Households | 1993 |
| Sexperiment Limited | Other services | 2025 |
| Sf&O Development Projects Ltd | Construction | 2021 |
| Sgreene Limited | Arts & recreation | 2023 |
| Shadowgraph Ltd | Information & communication | 2022 |
| Shakespeare Road RTM Company Limited | Professional & scientific | 2013 |
| Shandclarke Consulting Ltd | Professional & scientific | 2020 |
| Sharestep Ltd | Information & communication | 2023 |
| Shearer Marshall Ltd | Construction | 2015 |
| Shell & FIN Ltd | Hospitality | 2025 |
| Shellsboro Limited | Professional & scientific | 2014 |
| Shepherds Residential Ltd | Real estate | 2025 |
| Shiels-Heath Limited | Wholesale & retail | 2026 |
| Shoot Puglia Location (UK ) Ltd | Professional & scientific | 2025 |
| Shoppers Warehouse Limited | Wholesale & retail | 2025 |
| Shree Realty Ltd | Real estate | 2025 |
| Side Hustle Events Ltd | Hospitality | 2025 |
| Sideshow Modern Limited | Wholesale & retail | 2022 |
| Silchester House Committee Ltd | Households | 2016 |
| Silver Hill Launderette Ltd | Other services | 2021 |
| Silverdale Court Management (Eastbourne) Limited | Households | 2011 |
| Silvertone Systems Limited | Real estate | 2001 |
| Simba Films Limited | Other services | 2010 |
| Simon Ainsworth Engineering Limited | Wholesale & retail | 2012 |
| Simple Tanning Solutions Ltd | Other services | 2024 |
| Simpsons Uckfield Limited | Wholesale & retail | 2004 |
| Sirius Business Improvements Limited | Manufacturing | 2025 |
| Sister Nell Limited | Information & communication | 2020 |
| SIT in the Van Construction Limited | Construction | 2017 |
| Site Craft Ltd | Manufacturing | 2019 |
| SIX the Mount Limited | Extraterritorial | 2017 |
| SJF Electrical Services Ltd | Construction | 2015 |
| Skiefer Ltd | Professional & scientific | 2014 |
| Sky Dining Ltd | Professional & scientific | 2023 |
| Skylark Digital Solutions Ltd | Information & communication | 2023 |
| Skylon Post Limited | Information & communication | 2014 |
| Sleeper Design Limited | Information & communication | 2015 |
| Slim Butcher Food Hall Ltd | Hospitality | 2024 |
| SLM Vehicle Management Limited | Wholesale & retail | 1988 |
| Slotkarn Limited | Real estate | 2017 |
| Smart Eating Solutions Ltd | Health & social care | 2015 |
| Smart Filaments Limited | Professional & scientific | 2021 |
| Smart Utility Management Limited | Energy | 2025 |
| SME Global Ltd | Financial services | 2025 |
| Smeck Trading Ltd | Wholesale & retail | 2020 |
| Snapbook Partners Limited | Professional & scientific | 2025 |
| Snapes Mechanical Services Limited | Professional & scientific | 2014 |
| Snug a BUG Ltd | Wholesale & retail | 2025 |