| SHM Support Limited | Professional & scientific | 2020 |
| Shoja Ltd | Hospitality | 2015 |
| Sholing Pharma Ltd | Wholesale & retail | 2023 |
| Shooting Show Limited | Extraterritorial | 2016 |
| Shoreline Contractors Ltd | Construction | 2018 |
| Shoreline Holdings (South) Ltd | Financial services | 2025 |
| Shoreline Rentals Ltd | Administrative & support | 2019 |
| Show Prepare Ltd | Other services | 2022 |
| Shree Vinayak Ltd | Wholesale & retail | 2026 |
| SHU College of International Education Limited | Education | 2026 |
| Siam Renovate Ltd | Construction | 2023 |
| SIB Consultancy Ltd | Education | 2024 |
| Sibilant Solutions Ltd | Information & communication | 2017 |
| Sigma Bond Ltd | Professional & scientific | 2020 |
| Sigma International Wealth Management Limited | Professional & scientific | 2015 |
| Signature Build & Renovation Limited | Construction | 2016 |
| Signblazer Ltd | Manufacturing | 2011 |
| Signbox Holdings Limited | Financial services | 2025 |
| Signbox Limited | Manufacturing | 1985 |
| Sika Sumi Ltd | Wholesale & retail | 2020 |
| Sika Sumi Properties Ltd | Real estate | 2025 |
| Siltbuster Process Solutions Limited | Water & waste | 2000 |
| Silver Birches Property Ltd | Real estate | 2021 |
| Silver Finch Group Ltd | Extraterritorial | 2024 |
| Silver Meadow Group Ltd | Extraterritorial | 2025 |
| Silver Moose Limited | Information & communication | 2008 |
| Silver Planet Limited | Professional & scientific | 2020 |
| SILVERDALE2 Ltd | Real estate | 2025 |
| Silverstar Healthcare Ltd | Professional & scientific | 2021 |
| Silvex Tree Surgeons Limited | Administrative & support | 2026 |
| SIM Racing Limited | Information & communication | 2003 |
| Simba's Dhaba Ltd | Hospitality | 2021 |
| Simon Lawson Ltd | Administrative & support | 2005 |
| Simon Macey Quality Homes Ltd | Construction | 2010 |
| Simple Tech Art Limited | Wholesale & retail | 2024 |
| Simply Snowsports Ltd | Administrative & support | 2013 |
| Simtex International Limited | Transport & logistics | 1995 |
| Sinez Medical Services Ltd. | Health & social care | 2024 |
| Sinorval Properties Ltd | Real estate | 2021 |
| SIR George of the Floofs Limited | Other services | 2023 |
| Sirus Limited | Information & communication | 2010 |
| Sirus Telecom Limited | Information & communication | 2010 |
| Sitezone Safety Limited | Wholesale & retail | 2016 |
| Sivco Limited | Information & communication | 2016 |
| Sivia Logistics Ltd | Transport & logistics | 2022 |
| SJ Hobbs Consultancy Ltd | Professional & scientific | 2022 |
| SJ Pharmaaesthetics Ltd | Professional & scientific | 2024 |
| SJ Shimlar Limited | Administrative & support | 2015 |
| SJB Builders (Southern Counties) Limited | Construction | 2000 |
| SJC Cars Limited | Wholesale & retail | 2012 |
| SJD Bookkeeping Limited | Professional & scientific | 2026 |
| SJD Property Solutions Limited | Construction | 2016 |
| SJG Finance Limited | Professional & scientific | 2013 |
| SJT Projects ( Tunbridge Wells ) Limited | Other services | 2017 |
| SJW Composites Ltd | Other services | 2021 |
| SK Systems Limited | Administrative & support | 2009 |
| Skeens & Wallace Ltd | Construction | 2023 |
| SKH Barbers Ltd | Other services | 2019 |
| Skills for Logistics Ltd | Education | 2015 |
| Skillsfirst Assess Ltd | Education | 2016 |
| Skillsfirst Awards Ltd | Education | 2009 |
| Skillsfirst Holdings Ltd | Financial services | 2014 |
| Skinner Haulage Ltd | Transport & logistics | 2023 |
| Skiptheq Ltd | Information & communication | 2022 |
| SKM Properties South Limited | Real estate | 2025 |
| Skma Foods Ltd | Hospitality | 2021 |
| Skua Projects Limited | Information & communication | 2009 |
| Sky Austria Ltd | Wholesale & retail | 2023 |
| Sky Prestige Services Limited | Wholesale & retail | 2017 |
| Sky Vape Shop Ltd | Wholesale & retail | 2026 |
| Skyline Systems Development Ltd | Information & communication | 2018 |
| Skyways Air Transportation UK Limited | Manufacturing | 2024 |
| SLC Group Holdings Limited | Manufacturing | 2002 |
| Sleena Healthcare Ltd | Health & social care | 2026 |
| SLG Vale Drive Limited | Real estate | 2019 |
| Slice Hair Academy Limited | Other services | 2020 |
| Slinger Construction Ltd | Administrative & support | 2015 |
| Slingshotsuk Ltd | Wholesale & retail | 2024 |
| SLS Clinic Limited | Other services | 2023 |
| SLS Enterprises Limited | Transport & logistics | 2012 |
| SLS Medispa Ltd | Other services | 2025 |
| Smack Burger Ltd | Hospitality | 2024 |
| Smallpiece Catering Limited | Hospitality | 2018 |
| Smart Homes (Southampton) Limited | Real estate | 2016 |
| Smart Homes (Southern) Limited | Real estate | 2003 |
| Smart Homes Holdings Ltd | Extraterritorial | 2019 |
| Smart Marketing Management Limited | Administrative & support | 2011 |
| Smart Techno Solutions Limited | Information & communication | 2017 |
| Smart Witt Limited | Wholesale & retail | 2024 |
| Smartmind Innovations Limited | Information & communication | 2023 |
| Smartscope Consulting Ltd | Information & communication | 2025 |
| Smile by Rudiak Limited | Health & social care | 2012 |
| Smile Computer Solutions Ltd | Information & communication | 2009 |
| Smith Fitness Personal Training Ltd | Other services | 2023 |
| Smiths Bakers Limited | Wholesale & retail | 2018 |
| SMJ Business Services Holdings Ltd | Other services | 2022 |
| Smjr Ltd | Professional & scientific | 2019 |
| SMR (Contracting) Limited | Professional & scientific | 2003 |
| SMS Consultancy and Marketing Limited | Professional & scientific | 2025 |
| Snappy Waste Services Limited | Water & waste | 2016 |