| LAL Services Ltd | Transport & logistics | 2025 |
| Landguard Fort Trust | Education | 1995 |
| Lanyards (Felixstowe) Freehold Limited | Households | 2022 |
| Larlhams Limited | Construction | 2000 |
| Larlhams Properties Ltd | Real estate | 2020 |
| Larry Services Ltd | Transport & logistics | 2016 |
| Lashing Systems Ltd | Transport & logistics | 2013 |
| Last Agriculture Ltd | Agriculture & fishing | 2026 |
| Last Hire & Renovations Ltd | Construction | 2019 |
| Last Property Rentals Ltd | Real estate | 2024 |
| LD Print Promotions Ltd | Manufacturing | 2012 |
| LDM Loca Ltd | Hospitality | 2024 |
| LE Riche (Felixstowe) Limited | Other services | 2015 |
| Ledger-Tech Limited | Professional & scientific | 2003 |
| Lendexa Ltd | Information & communication | 2025 |
| Leogistics Ltd | Transport & logistics | 2021 |
| Lerros Property Limited | Real estate | 1970 |
| Leszko. Ltd | Transport & logistics | 2023 |
| Let's Play Games Limited | Other services | 2003 |
| Let's Talk Women's Health CIC | Health & social care | 2025 |
| Levelridge Transport Limited | Transport & logistics | 2002 |
| Levington Court Management (1995) Limited | Real estate | 1995 |
| LFS Services Ltd | Transport & logistics | 2016 |
| LHC (Mmfs) Ltd | Health & social care | 2023 |
| Lidarses Ltd | Transport & logistics | 2024 |
| Lift Edge Ltd | Administrative & support | 2025 |
| Lillydean 888 Limited | Wholesale & retail | 2021 |
| Lilybrook Garden Nature Ltd | Wholesale & retail | 2025 |
| Lindsay F Wark Ltd | Professional & scientific | 2021 |
| Link Sites Limited | Transport & logistics | 2013 |
| Lithouse CIC | Professional & scientific | 2024 |
| Little Dreams Ltd | Hospitality | 2023 |
| Live Life on the VEG Ltd | Administrative & support | 2020 |
| Living Life on the VEG Ltd | Administrative & support | 2020 |
| Liza Trans Ltd | Other services | 2019 |
| LKM Properties Ltd | Real estate | 2015 |
| LMB Factory Ltd | Transport & logistics | 2024 |
| LN Aesthetics Skin and Health Clinic Ltd | Health & social care | 2020 |
| Local Shop Felixstowe Ltd | Wholesale & retail | 2025 |
| LOCKSMITH4U Ltd | Construction | 2025 |
| Logistics Information Network Enterprise (UK) Limited | Professional & scientific | 1999 |
| Logistics Marketing Ltd | Professional & scientific | 2022 |
| Lokon Ltd | Transport & logistics | 2023 |
| Loksborough Limited | Financial services | 2021 |
| Loly Trans Ltd | Transport & logistics | 2023 |
| London Thamesport Investments Limited | Financial services | 2008 |
| London Thamesport Limited | Professional & scientific | 1987 |
| Look Sharp Hair Ltd | Other services | 2022 |
| Louella Violet Ltd. | Professional & scientific | 2025 |
| Lovebarre Ltd | Other services | 2025 |
| LRH Ltd | Professional & scientific | 2019 |
| Luckpaw Limited | Wholesale & retail | 2025 |
| Lukasz Krawiec Ltd | Transport & logistics | 2014 |
| Lumora Brand Ltd | Wholesale & retail | 2024 |
| LV Caspian Limited | Transport & logistics | 2014 |
| LV Shipping Holdings Limited | Financial services | 2002 |
| LV Valenbeck Limited | Manufacturing | 2006 |
| M & J H Investments Limited | Real estate | 2017 |
| M J Harris Ltd | Manufacturing | 2013 |
| M&B Bespoke Refurbishments Limited | Construction | 2017 |
| Mabbott Group Construction & Renovations Ltd | Construction | 2026 |
| Mabbott Group Holdings Ltd | Real estate | 2026 |
| Mabbott Group Home Ltd | Wholesale & retail | 2026 |
| Mabbott Group Ltd | Manufacturing | 2023 |
| Mack Developments Ltd | Real estate | 2021 |
| Magnum Book Services Limited | Transport & logistics | 2009 |
| Magnum Group Holdings Limited | Financial services | 2009 |
| Magnum Spedition Limited | Transport & logistics | 1989 |
| Mahdi Shop Ltd | Wholesale & retail | 2024 |
| Main Sale Consultancy Limited | Professional & scientific | 2018 |
| Mainstay Property Investments Ltd | Real estate | 2002 |
| Maitland Commercials Limited | Information & communication | 2009 |
| Manning Amusement Parks Limited | Arts & recreation | 1996 |
| MAP Photography Limited | Professional & scientific | 2017 |
| MAR 200 Services Ltd | Transport & logistics | 2024 |
| Marad Holdings Ltd | Real estate | 2025 |
| Maranick Transport Ltd | Transport & logistics | 2019 |
| Marianotransport Limited | Transport & logistics | 2021 |
| Marin Transport Ltd | Transport & logistics | 2024 |
| Mariner Gardens Limited | Households | 2021 |
| Maritime Cargo Processing P.L.C. | Transport & logistics | 1985 |
| Maritime Group Limited | Transport & logistics | 2001 |
| Maritime Transport Limited | Transport & logistics | 1974 |
| Maritime Transport Services Limited | Transport & logistics | 1989 |
| Maritime Transport Services Pension Trustee Limited | Administrative & support | 2002 |
| Marius 79 Ltd | Transport & logistics | 2019 |
| Marnertrans Ltd | Transport & logistics | 2024 |
| Marshall Investments (UK) Limited | Administrative & support | 2003 |
| Martello Park Catering Limited | Hospitality | 2016 |
| Martello Place Management Limited | Households | 1994 |
| Martello R Management Company Limited | Households | 2014 |
| Martello Transport Limited | Transport & logistics | 2017 |
| Martin Bott (Bookdealers) Limited | Wholesale & retail | 1996 |
| Marv Services Ltd | Transport & logistics | 2016 |
| Maryo Damian Ltd | Transport & logistics | 2020 |
| Master Marine Limited | Extraterritorial | 1995 |
| MAT Estates Ltd | Real estate | 2026 |
| Mat&Maz Transport Ltd | Transport & logistics | 2020 |
| Mat&Mzl Ltd | Transport & logistics | 2019 |
| Mayan Rainforest Co. Limited | Wholesale & retail | 2008 |