| Summit Marine Ltd | Manufacturing | 2025 |
| Summit Recruitment Limited | Administrative & support | 2014 |
| Sumol Sunil Ltd | Administrative & support | 2025 |
| Sun City Tanning Lounge Ltd | Other services | 2026 |
| Sun Fashion Limited | Manufacturing | 2008 |
| Sun Properties 777 Limited | Real estate | 2024 |
| Sun Property 666 Limited | Real estate | 2023 |
| Sun Property 888 Limited | Real estate | 2021 |
| Sun South Solar Limited | Construction | 2025 |
| Sun Star Impex Ltd | Administrative & support | 2024 |
| SUN2SHINE Properties Limited | Real estate | 2025 |
| Sunassee Limited | Hospitality | 2012 |
| Sunbed Rooms Limited | Administrative & support | 2022 |
| Sunblink Ltd | Administrative & support | 2019 |
| Suncity Southampton Ltd | Hospitality | 2017 |
| Sundaes Funtime Ltd | Hospitality | 2019 |
| Sundaes G Ltd | Hospitality | 2019 |
| Sunday Service Agency Ltd | Information & communication | 2024 |
| Sunderland Chippy Ltd | Hospitality | 2024 |
| Sundowner RTM Company Limited | Households | 2011 |
| Sundrop Studio Ltd | Wholesale & retail | 2024 |
| Sunflower TTM Ltd | Administrative & support | 2023 |
| Sunfun Fabrics Limited | Wholesale & retail | 2025 |
| Sunna Fightwear Ltd | Wholesale & retail | 2025 |
| Sunniva Fusion Ltd | Information & communication | 2026 |
| Sunny Hounds Limited | Wholesale & retail | 2020 |
| Sunny Locum Ltd | Public administration | 2024 |
| Sunnycroft Residential Care Home Ltd | Health & social care | 2003 |
| Sunnydale Farm Touring Park Limited | Hospitality | 2017 |
| Sunnyday International Foods Ltd | Wholesale & retail | 2023 |
| Sunnyfield Rise Property Management Ltd | Households | 2008 |
| Sunnyhill Holdings Ltd | Professional & scientific | 2025 |
| Sunnyhollow Property's Limited | Real estate | 2024 |
| Sunnylives Support Ltd | Public administration | 2019 |
| Sunrise Assetts & Autos Limited | Wholesale & retail | 2022 |
| Sunrise Golf Ukeig | | 2008 |
| Sunset Red Limited | Real estate | 2008 |
| Sunshine Contracts Limited | Households | 1995 |
| Sunshine Travel & Tourist Limited | Professional & scientific | 2004 |
| Sunstorm Covers Limited | Manufacturing | 2023 |
| Sunstorm Marine Limited | Wholesale & retail | 2023 |
| Supaflo Marine Services Limited | | 1976 |
| Super Chef Southampton Ltd | Hospitality | 2026 |
| Super Estates Limited | Real estate | 1935 |
| Super Global Trade Ltd | Wholesale & retail | 2025 |
| Super Prime Fitness Ltd | Wholesale & retail | 2024 |
| Super SAM Southampton Ltd | Wholesale & retail | 2019 |
| Super WOK (Southampton) Ltd | Hospitality | 2021 |
| Supercar Spares Ltd | Wholesale & retail | 2023 |
| Superdrive Junior Academy Ltd | Education | 2023 |
| Superfli Limited | Financial services | 2022 |
| Superhero Pudding Limited | Professional & scientific | 2019 |
| Superior Cleaning Services Limited | Administrative & support | 1993 |
| Supermarine SPV Ltd | Financial services | 2021 |
| Superreel Productions Ltd | Information & communication | 2012 |
| Superschools Limited | Arts & recreation | 2013 |
| Supervision & Training Consultancy Ltd | Professional & scientific | 2020 |
| Superyacht Agency Services (Southampton) Limited | Professional & scientific | 1989 |
| Superyacht Career Ltd | Information & communication | 2022 |
| Superyacht Fitness Ltd | Wholesale & retail | 2022 |
| Superyacht Solutions LLP | | 2009 |
| Superyacht Technical Services Limited | Professional & scientific | 2010 |
| Supper Utensils Ltd | Wholesale & retail | 2024 |
| Supply Snap Ltd | Wholesale & retail | 2026 |
| Support Buddies Hampshire Ltd | Health & social care | 2026 |
| Support Buddies Ltd | Health & social care | 2019 |
| SUPPORT2CARE Ltd | Administrative & support | 2025 |
| Supportedplace Ltd | Health & social care | 2025 |
| Supporters Projects Ltd | Construction | 2023 |
| Supremacy Roof Care Ltd | Construction | 2022 |
| Supreme Freight Services Limited | Transport & logistics | 1986 |
| Supreme Handtools Limited | Wholesale & retail | 2024 |
| Supreme International Shipping Limited | Extraterritorial | 1995 |
| Supreme South Cleaning Services Ltd | Administrative & support | 2023 |
| Supreme UK Group Limited | Construction | 2020 |
| Suraiya Dinning Limited | Hospitality | 2025 |
| Surepath Enterprises Ltd | Administrative & support | 2026 |
| Surewise Consultancy Ltd | Wholesale & retail | 2023 |
| Surf Break Ltd | Transport & logistics | 2018 |
| Surrey and London Urology Ltd | Health & social care | 2018 |
| Surs by URS Limited | Other services | 2021 |
| Surus Consulting Limited | Information & communication | 2012 |
| Survana Ltd | Wholesale & retail | 2024 |
| SUS Pro Group Ltd | Wholesale & retail | 2003 |
| Susan Katrina Walsh Limited | Administrative & support | 2017 |
| Susannah Bourne Communications Ltd | Professional & scientific | 2015 |
| Sushi Online Limited | Information & communication | 2015 |
| Sussex Carpet Brokers Limited | Wholesale & retail | 1997 |
| Sussex Road Developments Ltd | Households | 2018 |
| Sustain Wood Essence Ltd | Wholesale & retail | 2025 |
| Sustainable Acoustics Ltd | Professional & scientific | 2012 |
| Sustainable Criminal Justice Solutions Community Interest Company | Professional & scientific | 2011 |
| Sustainable Office Solutions Limited | Wholesale & retail | 2021 |
| Sustainance Limited | Information & communication | 2024 |
| Sustainsphere Advisory Ltd | Professional & scientific | 2024 |
| Susu Social Enterprises Ltd | Real estate | 2014 |
| Sutcliffe and SON Limited | Wholesale & retail | 2007 |
| Sutcliffes Maritime (UK) Limited | Transport & logistics | 2008 |
| Sutton Estate Holdings Ltd | Real estate | 2024 |
| Suvic Products Limited | Manufacturing | 1991 |