| Lemon Tree Day Nursery (Portsmouth) Limited | Education | 2025 |
| Lemon Tree Flooring Ltd | Wholesale & retail | 2011 |
| Lemonade Legal Ltd | Professional & scientific | 2024 |
| LEN Harfield Limited | Wholesale & retail | 1963 |
| Lendrum's Driving School (Southampton) Ltd | Other services | 2015 |
| Lens-Tech Company Limited | Wholesale & retail | 2014 |
| Lensworks Ltd | Professional & scientific | 2024 |
| Lentel Ltd | Information & communication | 2021 |
| LEO Communications Ltd | Information & communication | 2021 |
| LEO Facade Holdings Limited | Professional & scientific | 2024 |
| Leo's Barber Salon Limited | Other services | 2022 |
| Leo's Hotel Ltd | Hospitality | 2020 |
| Leo.Al.Auto Ltd | Transport & logistics | 2017 |
| Leoma Ltd | Wholesale & retail | 2019 |
| Leon Rose Ltd | Other services | 2020 |
| Leonard Charles Wealth Ltd | Financial services | 2022 |
| Leonard Legal Ltd | Professional & scientific | 2017 |
| Leonard Solicitors LLP | | 2016 |
| Leonor Ltd | Construction | 2016 |
| Leonovandreea Limited | Health & social care | 2022 |
| Leric Ltd | Construction | 2025 |
| Lerodea Limited | Real estate | 2017 |
| LES Betises Ltd | Hospitality | 2018 |
| LES Finance Co Limited | Financial services | 2019 |
| LES Preston TV Video Repairs Limited | Other services | 1995 |
| Lesgo Limited | Health & social care | 2014 |
| Lesley Kirk & Co Ltd | Professional & scientific | 2019 |
| Lest Investments | Financial services | 2016 |
| LET From US Ltd | Households | 2019 |
| LET IT Shine South Ltd | Administrative & support | 2024 |
| Lets Elevate Ltd | Administrative & support | 2026 |
| Lets GET Cleaned Ltd | Administrative & support | 2023 |
| Lets GET Dressed Ltd | Professional & scientific | 2021 |
| Lets Padel Ltd | Arts & recreation | 2024 |
| Lets Rent Southampton Properties Ltd | Households | 2013 |
| Letterlove Ltd | Professional & scientific | 2021 |
| Letts Real Estate Limited | Real estate | 2025 |
| Letts Share Ltd | Real estate | 2017 |
| Level Best Concreting Ltd | Wholesale & retail | 2004 |
| Level UP Cleaning Services Limited | Administrative & support | 2017 |
| Levent Trading Ltd | Wholesale & retail | 2024 |
| Leventhorpe Limited | Households | 1997 |
| Lever Operations & Risk Ltd | Professional & scientific | 2026 |
| Levillard Ltd | Real estate | 2015 |
| Lewis & Richardson Roofing Services Limited | Construction | 1999 |
| Lewis J Mitchell Painting & Decorating Limited | Construction | 2020 |
| Lewis Salmon Group Ltd | Construction | 2023 |
| LEX22 Ltd | Transport & logistics | 2022 |
| Lexa Group Limited | Construction | 2016 |
| Lexa Property Ltd | Real estate | 2021 |
| LEXLEY0093 Healthcare Limited | Health & social care | 2015 |
| Lextech Ltd | Information & communication | 2025 |
| Lexturesouth Limited | Wholesale & retail | 2025 |
| Leymay Ltd | Real estate | 2017 |
| Leystar Limited | Professional & scientific | 1995 |
| LFA Recruitment Limited | Administrative & support | 2026 |
| LFR Holdings Limited | Financial services | 2016 |
| LG Carpentry & Conservatory Specialists Ltd | Manufacturing | 2022 |
| LG Lock and Security Ltd | Other services | 2010 |
| LG Planning Ltd. | Professional & scientific | 2012 |
| LG Vision Limited | Information & communication | 2021 |
| LG87 Limited | Transport & logistics | 2023 |
| LGC Fareham Limited | Wholesale & retail | 2023 |
| LGC Plumbing & Heating Ltd | Construction | 2019 |
| LGC Property Group Ltd | Real estate | 2025 |
| LGD Southampton Limited | Other services | 2026 |
| LGL Technical Services Limited | Other services | 2019 |
| LGM Education Consultant Limited | Education | 2019 |
| LGM Trans Ltd | Transport & logistics | 2019 |
| Lgrw Tree Care Ltd | Administrative & support | 2026 |
| LGS Management Ltd | Administrative & support | 2022 |
| LH Construction Projects UK Limited | Construction | 2025 |
| LH Home Solutions Limited | Construction | 2020 |
| LHD Ventilation Ltd | Construction | 2014 |
| LHG Property Ltd | Real estate | 2014 |
| LHM Property Services Limited | Construction | 2006 |
| Li-Li & Paise Play House Ltd | Health & social care | 2025 |
| Liable Rain Limited | Wholesale & retail | 2025 |
| Liam Crook Ltd | Manufacturing | 2019 |
| Liam Holmes Ltd | Construction | 2021 |
| Liam Lucas Limited | Construction | 2014 |
| Libas Milli Ltd | Wholesale & retail | 2026 |
| Liberatii Ltd | Information & communication | 2019 |
| Libertate Holdings Limited | Financial services | 2024 |
| Liberty Asset Finance Limited | Extraterritorial | 2020 |
| Liberty Court Management Limited | Households | 1999 |
| Liberty Finance Limited | Financial services | 2001 |
| Liberty Green Live Limited | Health & social care | 2015 |
| Liberty Green Ltd | Wholesale & retail | 2024 |
| Liberty Leasing Limited | Financial services | 2022 |
| Liberty Leasing Trustees Limited | Administrative & support | 2022 |
| Licc Design Co. Ltd | Professional & scientific | 2021 |
| Licenced Recycling UK Ltd | Wholesale & retail | 2022 |
| Licensed Taxi Limited | Transport & logistics | 2020 |
| Licensed Taxi Southampton Limited | Transport & logistics | 2026 |
| Licit Consulting Ltd | Information & communication | 2016 |
| Liddiard Portfolio Ltd | Real estate | 2026 |
| LIF Holdings Limited | Financial services | 1994 |
| Life Changes Counselling | Health & social care | 2006 |
| Life Effect Chiropractic (Southampton) Limited | Health & social care | 2022 |