| Street King Ltd | Wholesale & retail | 2024 |
| Street Ride Limited | Transport & logistics | 2023 |
| Stretch Zone Consulting Ltd | Professional & scientific | 2020 |
| Stride LAB Limited | Information & communication | 2021 |
| Stride Recruitment Limited | Extraterritorial | 2017 |
| Striketype Ltd | Information & communication | 2014 |
| Stripy Lightbulb CIC | Education | 2018 |
| Strong Anchor Project CIC | Arts & recreation | 2026 |
| Strong Back Nutrition Ltd | Manufacturing | 2026 |
| Strong Island Recordings Ltd | Information & communication | 2017 |
| Stronger Together Community CIC | Health & social care | 2025 |
| Strophe Ltd | Administrative & support | 2013 |
| Strr Ltd | Construction | 2026 |
| Structures Group Limited | Manufacturing | 2017 |
| Stuart Court (Cosham) Freehold Limited | Households | 2018 |
| Stuart Ryan Groundworks Ltd | Construction | 2019 |
| Student Welfare Association Portsmouth CIC | Professional & scientific | 2024 |
| Studio 8 Aesthetic Solutions Limited | Other services | 2017 |
| Studio 8 Beauty Limited | Wholesale & retail | 2013 |
| Studio 8 Group Limited | Financial services | 2017 |
| Studio Demain Ltd | Professional & scientific | 2025 |
| Studio Grey Investments Limited | Real estate | 2019 |
| Studio X11 Ltd | Information & communication | 2022 |
| Studyera Recruitment Agency Ltd | Education | 2024 |
| Subash Kumar Ltd | Construction | 2019 |
| Subbie Hub (the Subcontractors Directory) Ltd | Information & communication | 2025 |
| Subcable Limited | Information & communication | 2018 |
| Submitdeal Limited | Real estate | 1992 |
| Subsea Craft Limited | Manufacturing | 2014 |
| Subsea Craft UK (Holdings) Limited | Financial services | 2026 |
| Substation Design Services Limited | Administrative & support | 2006 |
| Subsuper Limited | Hospitality | 2015 |
| Sueco UK Limited | Manufacturing | 2008 |
| Sufficient Health Care Ltd | Health & social care | 2021 |
| Sugar and Whisk Stirring UP Happiness Ltd | Hospitality | 2025 |
| Sugarlocks Limited | Other services | 2025 |
| Suisse Autoturn Limited | Manufacturing | 1992 |
| Suite Hosts Limited | Administrative & support | 2018 |
| Sujana Limited | Real estate | 2013 |
| Sullivan Holdings Group Limited | Real estate | 2020 |
| Sullivan Trading Co Ltd | Financial services | 2026 |
| Sumayyah-Enterprises Ltd | Other services | 2015 |
| Summer Beach Festival Ltd | Arts & recreation | 2021 |
| Summerden Property LLP | | 2015 |
| Summit Interior Fit-Outs Ltd | Manufacturing | 2026 |
| Summit Scaffold Limited | Construction | 2025 |
| Sun Court Freehold Limited | Households | 2003 |
| Sun Rising Management Limited | Hospitality | 2019 |
| Sunflower Chinese Restaurant Ltd | Hospitality | 2024 |
| Sunnahhealth Ltd | Health & social care | 2021 |
| Sunny Clothing Limited | Wholesale & retail | 2025 |
| Sunny Fish Bar Limited | Hospitality | 2012 |
| Sunnyside UK Developments Ltd | Construction | 2025 |
| Sunray Productions Ltd | Information & communication | 2020 |
| Sunrise Dairy Limited | Wholesale & retail | 2013 |
| Sunrise Laundry Portsmouth Ltd | Other services | 2022 |
| Supamodel Technology Ltd | Other services | 2026 |
| Super Burger Ltd | Hospitality | 2019 |
| Super Eleven Shake Ltd | Manufacturing | 2013 |
| Super Kebab House (Portsmouth) Limited | Hospitality | 2024 |
| Super Rides UK Ltd | Arts & recreation | 2023 |
| SUPER5IVES Paintball Ltd | Wholesale & retail | 2015 |
| SUPER73 UK Limited | Manufacturing | 2023 |
| Superior Roofing Specialist Ltd | Construction | 2025 |
| Supernatural Tours Limited | Administrative & support | 2008 |
| Superstar Schools Ltd | Arts & recreation | 2013 |
| Supertips Limited | Education | 2010 |
| Superyacht Consultancy Limited | Professional & scientific | 2012 |
| Supply Only Playground Markings Limited | Professional & scientific | 2019 |
| Supreme Logistics Transport Ltd | Transport & logistics | 2010 |
| Supreme Roofing and Building Ltd | Construction | 2017 |
| Supremo Healthcare Services (UK) Limited | Wholesale & retail | 2024 |
| Sure Bond Roof Systems Limited | Construction | 1998 |
| Sure Steps Day Nursery Limited | Other services | 2005 |
| Surehold Property Limited | Real estate | 2022 |
| Surepath Recruitment Ltd | Administrative & support | 2025 |
| Suricata Homes Limited | Real estate | 2016 |
| Suro Contractors Ltd | Construction | 2025 |
| Surrey & Berkshire Scaffolding Ltd | Construction | 2020 |
| Surrey Floor Restoration Ltd | Construction | 2024 |
| Surrey Shared Limited | Real estate | 2016 |
| Survey Drones Ltd | Professional & scientific | 2024 |
| Sushiology Limited | Hospitality | 2023 |
| Sussex Airport CAB Ltd | Transport & logistics | 2020 |
| Sussex Food Partnership Limited | Wholesale & retail | 2010 |
| Sussex Pool Maintenance Ltd | Other services | 2023 |
| Sussex Woodlands Ltd | Other services | 2008 |
| Sustainable Fire Protection Limited | Other services | 2023 |
| Sutton Neighbourhood's CIC | Health & social care | 2023 |
| Sutton Pcns (Primary Care Networks) Community Interest Company | Health & social care | 2015 |
| Suzanne Andrews Limited | Wholesale & retail | 2005 |
| SVG Automotive Ltd | Wholesale & retail | 2023 |
| SVK (Aylesbury) Properties Limited | Real estate | 2022 |
| SW Domus Ltd | Extraterritorial | 2023 |
| Swafe Holdings Ltd | Financial services | 2026 |
| Swallows Volvo Specialist Ltd | Wholesale & retail | 2018 |
| Swan Recruitment Limited | Administrative & support | 1992 |
| Swann 123 Limited | Real estate | 2026 |
| Swanns Electrical Limited | Construction | 2019 |
| Sweet Briar Sweets Limited | Manufacturing | 2026 |