| Stonemind Studio Ltd | Education | 2026 |
| Stop & Vape Limited | Wholesale & retail | 2019 |
| Stop.Breathe.Think. | Health & social care | 2023 |
| Stopped Clock Ltd | Hospitality | 2008 |
| Store Bay Holdings Ltd | Real estate | 2018 |
| Storeton Capital Limited | Financial services | 2015 |
| Stormport Limited | Households | 1991 |
| Stormproof Roofing & Cladding Limited | Construction | 1998 |
| Story Developments (Brighton) Ltd | Real estate | 2024 |
| Story Developments Brighton and Hove Ltd | Real estate | 2025 |
| Story Kingsway Ltd | Real estate | 2024 |
| Storytime Films Ltd | Information & communication | 2011 |
| Stowbridge Solar 1 Limited | Energy | 2013 |
| STR Construction Ltd | Wholesale & retail | 2024 |
| Strategicasiaeurope Ltd. | Professional & scientific | 2011 |
| Stratexon Ltd | Information & communication | 2023 |
| Stratus Coaching Limited | Administrative & support | 2008 |
| Strawberry Fields London Limited | Wholesale & retail | 2009 |
| Street Scaffolding Limited | Construction | 2008 |
| Streetfunk Dance C.I.C. | Education | 2024 |
| Streethome Limited | Households | 1986 |
| Strength and Nutrition Limited | Health & social care | 2022 |
| Strength Leadership Ltd | Education | 2010 |
| Stretton Court (Hove) Management Company Limited | Households | 1992 |
| Strictly Blackpool Ltd | Hospitality | 2020 |
| Stride Healthcare Limited | Health & social care | 2016 |
| Strive Exhibitions Limited | Administrative & support | 2025 |
| Strong Words Limited | Professional & scientific | 2016 |
| Strongbok Limited | Wholesale & retail | 2022 |
| Stronglytyped Consulting Ltd | Information & communication | 2026 |
| Stuart Oliver Housing Limited | Construction | 2024 |
| Stuart Oliver Property Limited | Real estate | 2020 |
| Student Brighton Limited | Real estate | 1982 |
| Student Service International Limited | Administrative & support | 2003 |
| Studio 9 Design Ltd | Professional & scientific | 2018 |
| Studio 9 Destinations Ltd | Construction | 2023 |
| Studio Aiylo Ltd | Professional & scientific | 2020 |
| Studio Astragal Limited | Professional & scientific | 2013 |
| Studio Coldy Ltd | Professional & scientific | 2021 |
| Studio Eleven Advisory Ltd | Information & communication | 2025 |
| Studio Everett Ltd | Professional & scientific | 2022 |
| Studio Furthermore LLP | | 2015 |
| Studio Gabriel Ltd | Wholesale & retail | 2023 |
| Studio Lees Limited | Professional & scientific | 2023 |
| Studio Number 2 Ltd | Other services | 2025 |
| Studio Paints Limited | Information & communication | 2020 |
| Studio Pictures Ltd | Information & communication | 2019 |
| Studio Sensi Ltd. | Other services | 2024 |
| Studio Sparqs Ltd | Information & communication | 2024 |
| Studio Yoell Ltd | Professional & scientific | 2022 |
| Studio-Kmm Limited | Professional & scientific | 2025 |
| STUDIO54 Limited | Wholesale & retail | 2025 |
| Studiofab Limited | Professional & scientific | 2011 |
| Study FLO Ltd | Professional & scientific | 2025 |
| Sturdy Current Solutions Ltd | Construction | 2021 |
| Stusie LLP | | 2017 |
| Style and Smile by Mero Ltd | Other services | 2021 |
| Su.Trdz Ltd | Financial services | 2026 |
| Suay Tech Limited | Information & communication | 2017 |
| Subcult Joint Ltd | Information & communication | 2021 |
| Subzerostudio Limited | Professional & scientific | 2009 |
| Sucker Punch Productions Ltd | Information & communication | 2018 |
| Sudbury Solar Limited | Energy | 2014 |
| Sudmant Ltd | Professional & scientific | 2021 |
| Sugar Frog Ltd | Professional & scientific | 2019 |
| Sugar Street Limited | Real estate | 1998 |
| Sugartech Limited | Real estate | 2008 |
| Sugy Dental Ltd | Health & social care | 2019 |
| Suite DNA Limited | Administrative & support | 2017 |
| Sukie Limited | Wholesale & retail | 2004 |
| Sullys Coffee Limited | Wholesale & retail | 2024 |
| Summer Dune Medical Ltd | Health & social care | 2025 |
| Summit Electrical Sussex Ltd | Construction | 2025 |
| Sun Harvest Ltd | Wholesale & retail | 2007 |
| Sun Homes Overseas Ltd | Real estate | 2004 |
| Sun Land Traders Ltd. | Construction | 2017 |
| Sun Makara Limited | Wholesale & retail | 2024 |
| Sun of a Beach Sauna Ltd | Health & social care | 2024 |
| Suncatcher Renewables Ltd | Energy | 2022 |
| Sunflower Sangha Ltd | Other services | 2025 |
| Sungazer Limited | Information & communication | 2018 |
| Sunil Dispensing Limited | Health & social care | 2009 |
| Sunkissed Hair Tanning and Beauty Limited | Other services | 2019 |
| Sunlight Psychology UK Limited | Health & social care | 2024 |
| Sunny Garden Kitchen Limited | Hospitality | 2025 |
| Sunnybrook Project Services Limited | Professional & scientific | 2017 |
| Sunport Limited | Real estate | 1997 |
| Sunrise 24 HR. Services Limited | Health & social care | 2009 |
| Sunset Tree Ltd | Arts & recreation | 2021 |
| Sunshine Beauty Ltd | Health & social care | 2023 |
| Sunspot Investments Limited | Real estate | 2017 |
| Super Gym Ltd | Wholesale & retail | 2021 |
| Superama Limited | Arts & recreation | 2021 |
| Supercharged Events Limited | Arts & recreation | 2010 |
| Supergrizzly Limited | Administrative & support | 2010 |
| Superlooper Community Interest Company | Administrative & support | 2020 |
| Superstar Recruitment Services Ltd | Professional & scientific | 2022 |
| Suprasumo Ltd | Information & communication | 2014 |
| Supreme Catering Sussex Limited | Other services | 2018 |
| Supremefeature Limited | Construction | 1997 |