| Winchester Court Management (Southampton) Limited | Households | 1966 |
| Winchester Distillery Limited | Manufacturing | 2006 |
| Winchester Estates Limited | Manufacturing | 2015 |
| Winchester Highways Limited | Construction | 2021 |
| Winchester Jazz Festival Limited | Arts & recreation | 2016 |
| Winchester Kitchens Ltd | Wholesale & retail | 2005 |
| Winchester Mews Management Limited | Households | 1997 |
| Winchester Oak Limited | Extraterritorial | 2011 |
| Winchester Radio Taxis Limited | Transport & logistics | 2013 |
| Winchester Residential Sales Limited | Real estate | 2015 |
| Winchester Retreats Ltd | Real estate | 2022 |
| Winchester Scaffolding Limited | Construction | 2012 |
| Winchester School Transport Ltd | Transport & logistics | 2022 |
| Winchester Taxi and Cabs Limited | Transport & logistics | 2018 |
| Winchester Travel Limited | Transport & logistics | 2025 |
| Windhover Projects Limited | Extraterritorial | 1975 |
| Windmill Southampton Ltd | Real estate | 2016 |
| Windor Home Improvements Limited | Construction | 2018 |
| Window Consultancy (Southern) Limited | Administrative & support | 2009 |
| Windrush and Knightwood Management Company Limited | Households | 2010 |
| Windrush House RTM Company Limited | Households | 2007 |
| Windscope Ltd | Information & communication | 2023 |
| Windship Technology Limited | Professional & scientific | 2012 |
| Windsor Court Southampton RTM Company Ltd | Households | 2024 |
| Windward B&R Limited | Hospitality | 2017 |
| Windward Day Services Community Interest Company | Health & social care | 2008 |
| Wine Utopia Limited | Wholesale & retail | 2011 |
| Winged Wheels Ltd | Transport & logistics | 2024 |
| Wingo Piri Piri Limited | Hospitality | 2024 |
| Winhart & March Ltd | Real estate | 2023 |
| Winifigs Ltd | Wholesale & retail | 2024 |
| Winkle Street Management Limited | Households | 2000 |
| Winmelon Flat Management Limited | Households | 1990 |
| Winn Court RTM Company Limited | Households | 2023 |
| Winn Road (Beaulieu Court) Limited | Households | 1988 |
| Winn Road Management Co. Limited | Households | 1971 |
| Winning Strength Blueprint Ltd | Information & communication | 2021 |
| Winning Strength Ltd | Arts & recreation | 2009 |
| Winnmont Electrical Services Limited | Construction | 2025 |
| Winscombe Property Limited | Real estate | 2025 |
| Winston Hill Guest House Limited | Extraterritorial | 2013 |
| Winston Hill Lodge Limited | Extraterritorial | 2013 |
| Wintax Cars Hampshire Limited | Transport & logistics | 2024 |
| Wintax Cars Ltd | Transport & logistics | 2007 |
| Wintax Limited | Transport & logistics | 2016 |
| Winter Soldier Care Support UK Ltd | Health & social care | 2018 |
| Winterbothams Limited | Administrative & support | 2012 |
| Winterbottom & SON Ltd | Extraterritorial | 2024 |
| Winterbottom Wonders Ltd | Wholesale & retail | 2024 |
| Wintershill Events LLP | | 2020 |
| Winterton Farm Marloes Limited | Agriculture & fishing | 2021 |
| Wintrade International Ltd | Wholesale & retail | 2020 |
| WIP Consultancy Ltd | Professional & scientific | 2025 |
| Wirebird Connections Ltd | Information & communication | 2016 |
| Wisdom of Ragnar Ltd | Manufacturing | 2023 |
| Wise OWL Counselling and Coaching Limited | Health & social care | 2015 |
| Wiseguys Tech Support Limited | Information & communication | 2022 |
| Wisely Cars Ltd | Transport & logistics | 2020 |
| Wisely Financial Services Limited | Financial services | 2022 |
| Wisent Logistics Ltd | Transport & logistics | 2011 |
| Wiser Health & Social Care Limited | Education | 2019 |
| Wish 14 Care Limited | Health & social care | 2022 |
| Wishwood Joinery Limited | Construction | 2018 |
| Wispex UK Ltd | Transport & logistics | 2022 |
| Wisteria Mortgages Ltd | Financial services | 2024 |
| Wisteria Wealth Limited | Financial services | 2021 |
| Withit Licensing Limited | Professional & scientific | 2002 |
| Wittering Place (West Wittering) Management Company Limited | Households | 2024 |
| Witts Hill Fostering Limited | Health & social care | 2025 |
| Witwro Trans Ltd | Transport & logistics | 2015 |
| Wizard Recruitment Limited | Administrative & support | 2004 |
| Wizards of OSS Limited | Agriculture & fishing | 2000 |
| Wizgol Ltd | Manufacturing | 2018 |
| Wjds Venues Ltd | Hospitality | 2025 |
| Wjrco Ltd | Wholesale & retail | 2024 |
| WK Closers Ltd | Wholesale & retail | 2025 |
| WKC Southampton Limited | Hospitality | 2026 |
| WKCS2910 Limited | Administrative & support | 2008 |
| WLB Roofing Ltd | Construction | 2025 |
| WLS Pro Ltd | Manufacturing | 2024 |
| WM PSV Services Limited | Wholesale & retail | 2016 |
| WMK Holdings Limited | Real estate | 2025 |
| WMK Logistics Ltd | Transport & logistics | 2025 |
| Wmklproperty Ltd | Real estate | 2025 |
| WN Construction Limited | Construction | 2016 |
| Wnie Ltd | Other services | 2017 |
| WO Seng Ltd | Hospitality | 2024 |
| WOD Economics Ltd | Manufacturing | 2020 |
| Wodi Prints Ltd | Manufacturing | 2025 |
| Wojciech Kosek 1184 Limited | Transport & logistics | 2014 |
| Wolcox UK Limited | Real estate | 2025 |
| Wolf Coaching Limited | Education | 2022 |
| Wolfpack Accounting Limited | Professional & scientific | 2024 |
| Wollip Limited | Arts & recreation | 2022 |
| Wolven Industries Limited | Information & communication | 2025 |
| Wolverton Flats Ltd | Real estate | 2026 |
| Wonderberrys Coffee Shops Limited | Manufacturing | 2021 |
| Wonderland Cleaning Service Limited | Administrative & support | 2020 |
| Wonka Enterprises Limited | Professional & scientific | 2005 |
| Wood and Gillette Property Ltd | Real estate | 2024 |