| Starbreed Cleaning Services Ltd | Administrative & support | 2026 |
| Starbyte Software Ltd | Information & communication | 2025 |
| Starfish Personal Development and Coaching Limited | Professional & scientific | 2009 |
| Starfish Properties (Southampton) Limited | Real estate | 2016 |
| Starfish Support Services Limited | Health & social care | 2016 |
| Stargazer London Ltd | Manufacturing | 2024 |
| Starguard Technologies Ltd | Professional & scientific | 2025 |
| Starlight Healthcare Ltd | Real estate | 2016 |
| Starlight One Ltd | Information & communication | 2015 |
| Starlight Trampoline and Gymnastics C.I.C. | Arts & recreation | 2014 |
| Starling Distribution Services Ltd | Manufacturing | 2011 |
| Starry Dreams Ltd | Professional & scientific | 2025 |
| STARRY1HRCONSULTING Limited | Professional & scientific | 2013 |
| Starrynight Financial Services Ltd | Financial services | 2025 |
| Starship Real Estate Management Ukeig | | 2013 |
| Startaylor Ukeig | | 2007 |
| Startfree Limited | Households | 1996 |
| Startox (Bishops Waltham) Limited | Construction | 2013 |
| Startox Builders Limited | Construction | 2004 |
| Startup U Ltd | Administrative & support | 2016 |
| Statham Property Services Limited | Construction | 2012 |
| Station Garage (Park Gate) Limited | Wholesale & retail | 1999 |
| Station Motors Car Sales Limited | Wholesale & retail | 2002 |
| Stationsole Limited | Wholesale & retail | 2024 |
| Statler and Waldorf Studio Limited | Professional & scientific | 2021 |
| Status Electrical Limited | Construction | 2002 |
| Status Flooring Limited | Construction | 1979 |
| Statybos Limited | Real estate | 2024 |
| Stay a While Limited | Real estate | 2006 |
| Stay Calm Residential Limited | Real estate | 2020 |
| Stay Fresh Cleaning Ltd | Administrative & support | 2025 |
| Stay New Forest Services Ltd | Hospitality | 2024 |
| Stay Plus Serviced Accommodation Ltd | Hospitality | 2015 |
| Stay Refined Ltd | Real estate | 2024 |
| Stay Safe Environmental Ltd | Construction | 2026 |
| Stay Southampton Ltd | Hospitality | 2019 |
| Stay With Limited | Financial services | 2026 |
| Stayforfeng Ltd | Manufacturing | 2025 |
| Staying Afloat Ltd | Manufacturing | 2021 |
| Stazhin Limited | Financial services | 2025 |
| STB Express Ltd | Transport & logistics | 2025 |
| Stcw Ltd | Education | 2020 |
| Steam IOT Ltd. | Professional & scientific | 2019 |
| Stearman Carpentry Ltd | Manufacturing | 2026 |
| Steel Frame Repairs Ltd | Construction | 2021 |
| Steel Preservation(Southampton)Limited | | 1967 |
| Steele Cleaning Ltd | Administrative & support | 2024 |
| Steele Enterprises Limited | Hospitality | 2021 |
| Steele Research Limited | Administrative & support | 2021 |
| Steelstream Services Ltd | Construction | 2026 |
| Steelward Holdings Ltd | Real estate | 2019 |
| Steepdene Management Company Limited | Households | 1982 |
| Steepslope Ltd | Construction | 2009 |
| Stef 15 Limited | Transport & logistics | 2017 |
| Stefan Courier Ltd | Transport & logistics | 2024 |
| Stefan Miles Bespoke Carpentry Ltd | Manufacturing | 2022 |
| Stellar Freight Limited | Transport & logistics | 2026 |
| Stellar Life Ltd | Wholesale & retail | 2017 |
| Stellar Transport Ltd | Transport & logistics | 2024 |
| Stemen Solutions Ltd | Administrative & support | 2009 |
| Step by Step Construction Ltd | Construction | 2015 |
| Step by Step Financial Solutions Ltd | Financial services | 2014 |
| Step by Step Property Solutions Ltd | Real estate | 2019 |
| Step Change Design Ltd | Information & communication | 2014 |
| Step-In-Cart Ltd | Wholesale & retail | 2026 |
| Steph Tranter Coaching Limited | Other services | 2016 |
| Stephen Penfold Structural Engineer Limited | Construction | 2021 |
| Stephens and Stuarts Engineering Company Limited | Manufacturing | 1978 |
| Stephens and Stuarts Holdings Limited | Financial services | 2025 |
| Stephens Court Management Limited | Households | 2014 |
| Stephenson Enterprises Ltd | Financial services | 2025 |
| Stepping Stone Support CIC | Real estate | 2025 |
| Stepping Stones Children & Young People's Services Ltd | Health & social care | 2018 |
| Stepside Management Limited | Administrative & support | 2012 |
| Stepwise (Woolston) LLP | | 2021 |
| Sterious Investments Limited | Professional & scientific | 1999 |
| Sterling Business Limited | Administrative & support | 2002 |
| Sterling Connect Ltd | Transport & logistics | 2026 |
| Sterling Direct Ltd | Wholesale & retail | 2026 |
| Sterling Logistic Services Ltd | Transport & logistics | 2020 |
| Sterling Properties and Commodities Limited | Professional & scientific | 2019 |
| Sterling PUB Company Ltd. | Hospitality | 2019 |
| Sterling Training Limited | Education | 2015 |
| Stern Consulting Limited | Information & communication | 2017 |
| Stern Property Limited | Real estate | 2020 |
| Steve Adams Floor Coverings Ltd | Construction | 2002 |
| Steve Dalton Ltd | Professional & scientific | 2013 |
| Steve Green Ltd | Transport & logistics | 2012 |
| Steve Jones Carpentry Ltd | Construction | 2026 |
| Steve Martin GAS Boiler Specialist Ltd | Construction | 2025 |
| Steve Renyard Inspirations Limited | Agriculture & fishing | 2024 |
| Steve Sharpe Ltd | Information & communication | 2021 |
| Steve Taylor Decorating Limited | Construction | 2012 |
| Steveco Ltd | Professional & scientific | 2022 |
| Steven Photostudio Limited | Information & communication | 2024 |
| Stevenson Management Services Ltd | Professional & scientific | 2024 |
| Steward Carpentry Limited | Construction | 2015 |
| Stewards Corporation UK Ltd | Wholesale & retail | 2017 |
| Stewart Wilkins Ltd | Professional & scientific | 2019 |
| Stfa Ltd. | Administrative & support | 2014 |