| Seaview Court Management Company (Worthing) Limited | Households | 1970 |
| Seaward (Bognor Road) Limited | Construction | 2011 |
| Seaward Construction Limited | Construction | 2017 |
| Seaward Homes Limited | Construction | 2017 |
| Seawood Decking Limited | Construction | 1999 |
| Sebastians Kitchens Ltd | Construction | 2023 |
| Sebastianstorm Ltd | Wholesale & retail | 2017 |
| Sebatticus Limited | Manufacturing | 2024 |
| Second 2 None Security Ltd | Administrative & support | 2023 |
| Second Avenue Batchmere Management Limited | Households | 1988 |
| Secret Desires Events Limited | Administrative & support | 2026 |
| Secret Sessions Ibiza Limited | Arts & recreation | 2018 |
| Sector 106 Ltd | Professional & scientific | 2018 |
| Secure Construct Holdings Limited | Real estate | 2023 |
| Secure Construct Limited | Construction | 2018 |
| Secure Consult Ltd | Professional & scientific | 2021 |
| Secureship Ltd | Transport & logistics | 2025 |
| Seebolds Consulting Ltd | Information & communication | 2014 |
| Seesai Limited | Information & communication | 2016 |
| Sells Properties Ltd | Real estate | 2025 |
| Selsey Club Ltd | Hospitality | 2025 |
| Selsey Launderette Ltd | Other services | 2018 |
| Selsey Marine Services Ltd | Manufacturing | 2014 |
| Selsey Press Limited | Manufacturing | 1963 |
| Selsey Property Holdings Limited | Real estate | 2025 |
| Selsey Social Club C.I.C. | Hospitality | 2004 |
| Selst Property Limited | Real estate | 2021 |
| Selstar Fireworks Ltd | Wholesale & retail | 2009 |
| Selva Associates Ltd | Professional & scientific | 2012 |
| Semifreddo Bay Limited | Manufacturing | 2024 |
| Semistone Media Ltd | Professional & scientific | 2014 |
| Sempre Limited | Financial services | 2021 |
| Senator Gardens Management Company Limited | Households | 1995 |
| Sendateus Technologies Ltd | Wholesale & retail | 2014 |
| Sener Holdings Ltd | Professional & scientific | 2026 |
| Sengate Limited | Real estate | 1990 |
| Sense Safety Limited | Professional & scientific | 2021 |
| Sensor Shoes Limited | Professional & scientific | 2001 |
| SEO Solutions Limited | Information & communication | 2005 |
| Sequel Property Limited | Real estate | 2018 |
| Sequoia Ridge Capital Limited | Financial services | 2021 |
| Seraphim Consultancy Ltd | Professional & scientific | 2020 |
| Serino Limited | Extraterritorial | 2009 |
| Serious Sport Training Academy Ltd | Education | 2024 |
| Seriscent Ltd | Wholesale & retail | 2025 |
| Service Cover Company Limited | Other services | 2018 |
| Setonlea Ltd | Real estate | 2022 |
| Sevem Ltd | Real estate | 2022 |
| Seven Seas Logistics Limited | Transport & logistics | 2009 |
| Seven Sussex Ltd | Arts & recreation | 2025 |
| Sextant Marine Limited | Manufacturing | 2015 |
| SF Marine Limited | Professional & scientific | 2009 |
| SG Care Ltd | Health & social care | 2009 |
| SGC Property Developments Limited | Construction | 2013 |
| Sgsl Investments Ltd | Financial services | 2025 |
| Shaini Ltd | Health & social care | 2024 |
| Shaini Properties Ltd | Real estate | 2025 |
| Shake&Vape Limited | Construction | 2023 |
| Shakes and Pizza Limited | Hospitality | 2022 |
| Sham Holdings Limited | Professional & scientific | 1990 |
| Shareholder Corporate Finance Limited | Financial services | 2019 |
| Sharland Ventures Limited | Construction | 2023 |
| Sharmar Productions Ltd | Arts & recreation | 2005 |
| Sharply Studios Limited | Information & communication | 2025 |
| Sharrock Consulting Services Limited | Health & social care | 2024 |
| Sharuhen Ltd | Real estate | 2025 |
| Shaw Developments (Southern) Ltd | Real estate | 2018 |
| Sheillahill Farming LLP | | 2019 |
| Sheldon Court Management Company (Worthing) Limited | Households | 1967 |
| Shemara East Bracklesham Ltd | Households | 2022 |
| Shenton House Limited | Households | 1988 |
| Shepherd & Grantham Stonemasons Limited | Manufacturing | 2007 |
| Shepherd's Huts Sussex Ltd | Hospitality | 2024 |
| Sherden Limited | Administrative & support | 2002 |
| Shiny Facts Ltd | Manufacturing | 2023 |
| Shire Doorsets Ltd | Construction | 2024 |
| Shires Holdings Limited | Manufacturing | 2007 |
| Shoji Design Ltd | Manufacturing | 2025 |
| Shooting Industry Fund Limited | Other services | 2000 |
| Shoots Kebab Ltd | Hospitality | 2022 |
| Shop Bourne Limited | Wholesale & retail | 2024 |
| Shop With Natalie Limited | Professional & scientific | 2026 |
| Shopland Developments Limited | Construction | 2016 |
| Shopland Gray Developments Limited | Real estate | 2014 |
| Shopwhyke Storage Centre Ltd | Administrative & support | 2005 |
| Shopwyke Healthcare Ltd | Wholesale & retail | 2021 |
| Shore Financial Advisers Ltd | Financial services | 2005 |
| Shore Inn Ltd | Hospitality | 1997 |
| Shore Pets Ltd | Wholesale & retail | 2025 |
| Shore Secretaries Limited | Professional & scientific | 1997 |
| Shore Trustees Ltd | Professional & scientific | 2006 |
| Shore Watersports Limited | Wholesale & retail | 1992 |
| Shoreacre Ltd | Real estate | 2025 |
| Shorebreak Professional Services Limited | Professional & scientific | 2025 |
| Shoreham Silo Services Limited | Agriculture & fishing | 2004 |
| Shoreline Assets Limited | Extraterritorial | 1983 |
| Shoreline Defence Limited | Extraterritorial | 2022 |
| Shoreline Property Developments Limited | Construction | 2024 |
| Shoreline Yacht Transport Holding Limited | Transport & logistics | 2008 |
| Shorewholesalers Limited | Other services | 2025 |