| Shimizu Flowers Limited | Wholesale & retail | 2007 |
| Shiplu Fine Dine Ltd | Hospitality | 2025 |
| Shop Investments Ltd | Real estate | 2014 |
| Shore Marketing Ltd | Professional & scientific | 2016 |
| Shree Ganesh N&R Ltd | Hospitality | 2023 |
| Shugon Bags & Leather Goods Ltd | Wholesale & retail | 2003 |
| Shun DA Food Ltd | Hospitality | 2025 |
| Shyen Gold Ltd | Health & social care | 2025 |
| Siam Thai Brasserie Ltd | Hospitality | 2019 |
| Sibu Consulting Limited | Professional & scientific | 2024 |
| Sico Properties Limited | Extraterritorial | 2009 |
| Side by Side Accounting Limited | Professional & scientific | 2019 |
| Sidley Barbers Ltd | Other services | 2023 |
| Sidley Community Association | Health & social care | 1997 |
| Sidley Street Limited | Households | 2021 |
| Sign Master Creations Ltd | Manufacturing | 2025 |
| Siiziac Limited | Wholesale & retail | 2023 |
| Silver Sands Leisure Park Ltd | Hospitality | 2011 |
| Simon Francis Mastering Limited | Information & communication | 2016 |
| Simply Vision Limited | Wholesale & retail | 2019 |
| Sinteza Limited | Professional & scientific | 2025 |
| Sirius Plus Ltd | Health & social care | 2025 |
| Site Technical Services Ltd | Professional & scientific | 2019 |
| Siteseal Limited | Construction | 2024 |
| Siteseal Services Limited | Construction | 1978 |
| Sixways UP Ltd | Information & communication | 2022 |
| SJ Management Solutions Ltd | Information & communication | 2025 |
| SJD People Professionals Ltd | Administrative & support | 2023 |
| SJK Plumbing & Heating Limited | Construction | 2015 |
| Skiggs Limited | Construction | 2017 |
| Skiltek Clothing and Apparel Limited | Wholesale & retail | 2022 |
| Skiltek Limited | Arts & recreation | 2014 |
| Skiltek Travel Limited | Administrative & support | 2022 |
| Skyline Trading and Contracting Ltd | Wholesale & retail | 2023 |
| SLH Fish Limited | Wholesale & retail | 2006 |
| SLH Investments Limited | Real estate | 2017 |
| Slimmeria Devon Limited | Arts & recreation | 2019 |
| Slimmeria Limited | Arts & recreation | 2009 |
| Slipstream Lubricants Limited | Manufacturing | 2003 |
| SLT Bookkeeping Solutions Limited | Professional & scientific | 2021 |
| Small Properties Management Limited | Real estate | 2016 |
| Smith and Read Holdings Ltd | Real estate | 2023 |
| SMP Assets Ltd | Real estate | 2022 |
| Snappysnips Ltd | Other services | 2011 |
| Snowsfields Partners Ltd | Health & social care | 2020 |
| SO What IF Ltd | Professional & scientific | 2017 |
| Soap Health Limited | Information & communication | 2023 |
| SOL Investments TW Hastings Limited | Real estate | 2024 |
| Solomon’S E & Son’S Investment Ltd | Real estate | 2022 |
| Solomon’S E & Son’S Property Management LLP | | 2022 |
| Solstice-Re Limited | Professional & scientific | 2026 |
| Solution Focus Ltd | Information & communication | 2014 |
| Sonder Accounting Limited | Professional & scientific | 2001 |
| Sonder Data Systems Limited | Information & communication | 1996 |
| Sophie Wright Catering Ltd | Hospitality | 2007 |
| Soul and Sunrise Limited | Wholesale & retail | 2025 |
| Sourced Recruitment Limited | Administrative & support | 2016 |
| South Cliff Chalets (Bexhill Centre) Limited | Other services | 1958 |
| South Cliff Chalets (Bexhill East) Limited | Other services | 1958 |
| South Coast Court Construction Ltd | Construction | 2023 |
| South Coast Occupational Therapy Limited | Health & social care | 2008 |
| South East Apartments Ltd | Construction | 2019 |
| South Street Autos Limited | Wholesale & retail | 2023 |
| South Wharf Investments (Portslade) Limited | Real estate | 1889 |
| Southeast Electrical Solutions Limited | Professional & scientific | 2017 |
| Southerly Studio Limited | Professional & scientific | 2014 |
| Southern Caravan Services Limited | Professional & scientific | 2003 |
| Southern Counties Window Cleaning J Weir Limited | Administrative & support | 2018 |
| Southern Multi-Services Ltd | Manufacturing | 2018 |
| Southern Statics Ltd | Wholesale & retail | 2026 |
| Southern Utility Services Ltd | Water & waste | 2012 |
| Southwinds (Bexhill) RTM Company Limited | Other services | 2007 |
| Spark Product Creation Limited | Professional & scientific | 2011 |
| Sparks Light Haulage Services Ltd | Transport & logistics | 1998 |
| Spectrum Story LAB Ltd | Information & communication | 2026 |
| Spine Brickwork Ltd | Extraterritorial | 2023 |
| Splash Construction Ltd | Construction | 2025 |
| Splash Consultancy Ltd | Financial services | 2001 |
| Splash Investments Limited | Real estate | 2023 |
| Splash Plumbing Limited | Construction | 2005 |
| SPM Property Investments Ltd | Real estate | 2022 |
| Spoilt for Choice Limited | Hospitality | 1993 |
| Sprc Ltd | Households | 1969 |
| SPS Crawley Ltd | Wholesale & retail | 2018 |
| Square Compass Limited | Real estate | 2021 |
| SR Represents Limited | Professional & scientific | 2025 |
| SRI Ventures Ltd | Manufacturing | 2026 |
| SRK Sanjay Engineering Ltd | Construction | 2025 |
| ST George Corporation Limited | Hospitality | 2019 |
| ST Leonards Lodge Freehold Limited | Households | 2014 |
| ST Leonards Lodge RTM Company Limited | Households | 2006 |
| ST Leonards Plumbing & Heating Limited | Construction | 2024 |
| ST Vincent's Care Limited | Health & social care | 2005 |
| ST. Austin's Croft Limited | Households | 2002 |
| ST. Georges Court (Bexhill) Limited | Households | 2004 |
| ST. Marys Wood (Eara) Ltd | Administrative & support | 2016 |
| ST. Peter's Court (Bexhill) Limited | Professional & scientific | 2002 |
| Stable Mews Property Management Company Limited | Households | 2021 |
| Stacey Butler Ltd | Households | 2024 |
| Stalley Consultancy & Management Limited | Professional & scientific | 2018 |