| LLC Weymouth Limited | Extraterritorial | 2013 |
| Llgc Property Limited | Real estate | 2021 |
| Lloyd Davenport (Leisure) Limited | Hospitality | 1984 |
| LLP Property Investments Limited | Real estate | 2025 |
| LNG Property Group Ltd | Real estate | 2022 |
| Lobster POT (Portland Bill) Limited | Hospitality | 1961 |
| Loco Lobo TEX MEX Limited | Hospitality | 2019 |
| Lodge Way (Weymouth) Management Limited | Households | 2013 |
| Lodmoor Launderette Limited | Other services | 2014 |
| Loeffler Cobban Ltd | Professional & scientific | 2011 |
| Logical Electrics Limited | Administrative & support | 2007 |
| Lone Wolf Planning Limited | Administrative & support | 2024 |
| Long & Gilbert Limited | Extraterritorial | 2014 |
| Longlife Exhausts Ltd | Wholesale & retail | 1998 |
| Look UP Look Down Ltd | Information & communication | 2018 |
| Loose Moose Limited | Hospitality | 2016 |
| Loose Moose Motors Ltd | Other services | 2017 |
| Lopez Shackleford Ltd | Information & communication | 2016 |
| LOS Pablos Polo Equipment Ltd | Wholesale & retail | 2023 |
| Lotus Stores Ltd | Wholesale & retail | 2017 |
| Lovearts Digital Ltd | Manufacturing | 2023 |
| Lowestoft Investments Unlimited | Real estate | 2015 |
| LPM Cars Limited | Wholesale & retail | 2022 |
| LR Services Dorset Limited | Professional & scientific | 2021 |
| LSW Kitchens & Bathrooms Ltd | Extraterritorial | 2012 |
| LU Brazilian Hair Limited | Wholesale & retail | 2016 |
| Lube Finder Ltd | Wholesale & retail | 2019 |
| Lucas & Moore Electrical Limited | Construction | 2015 |
| Lucas Property Management Limited | Households | 1987 |
| Luder's Swiss Patisserie Limited | Manufacturing | 1964 |
| Lumosai Limited | Information & communication | 2024 |
| Luner Properties Ltd | Construction | 2019 |
| Lymeside Limited | Construction | 2026 |
| Lynch Court Weymouth Limited | Households | 1992 |
| Lynch Lane Garden Centre Limited | Wholesale & retail | 2008 |
| Lynch Lane Ltd | Wholesale & retail | 2024 |
| Lynch Lane Offices Limited | Real estate | 2009 |
| Lynton Charles Limited | Health & social care | 2012 |
| M & H Grocery Ltd | Wholesale & retail | 2024 |
| M & P Property Dorset LLP | | 2023 |
| M a Crabb Limited | Construction | 2002 |
| M and L Taverns Limited | Hospitality | 2024 |
| M C H Property Holdings Limited | Real estate | 2020 |
| M D Builders Dorset Ltd | Construction | 2024 |
| M D J French & Co Ltd | Health & social care | 2014 |
| M Franks Elec Limited | Professional & scientific | 2025 |
| M H Events Limited | Hospitality | 2015 |
| M H I S Limited | Information & communication | 2006 |
| M J Foice Building Ltd | Construction | 2014 |
| M Jackson Plastering Ltd | Construction | 2020 |
| M N E F Ltd | Education | 2020 |
| M PAY Contracting Ltd | Construction | 2019 |
| M R Golf LAB Ltd | Education | 2024 |
| M S Miah Limited | Hospitality | 2025 |
| M&Kt Associates Limited | Professional & scientific | 2016 |
| M&Kt Property Limited | Real estate | 2019 |
| M&S Property Innovations Ltd | Real estate | 2021 |
| M.A.D Decorators Ltd | Construction | 2013 |
| M.J.C. Builders Limited | Construction | 1992 |
| M.Y. Cleaning Services Limited | Other services | 2002 |
| Mabberley Limited | Information & communication | 2002 |
| Mabey Surfacing Ltd | Construction | 2018 |
| MAC 3 Barbers Dorchester Limited | Other services | 2024 |
| Macauley Consulting Limited | Administrative & support | 2022 |
| Macc Bricklaying and Construction Ltd | Construction | 2023 |
| MAD Mitch Whippy Ltd | Hospitality | 2025 |
| Made Management Limited | Hospitality | 2022 |
| MAG South West Limited | Administrative & support | 2024 |
| Magic Engineering Ltd | Energy | 2018 |
| Magical Days Boutique Ltd | Wholesale & retail | 2023 |
| Magicard Holdings Limited | Financial services | 2016 |
| Magicard Ltd | Manufacturing | 2016 |
| Magpie Aerospace Limited | Public administration | 2025 |
| Magpie Furniture Ltd | Manufacturing | 1963 |
| Magpies Chest Ltd | Extraterritorial | 2024 |
| MAH Electrical Contractors Limited | Energy | 2010 |
| Maiden Newton Stores Limited | Wholesale & retail | 2010 |
| Maidenview Properties Limited | Households | 2005 |
| Malaya LAH Inns Limited | Wholesale & retail | 2025 |
| Malcolm Middleton Limited | Construction | 2018 |
| Male Bros Ltd | Other services | 2018 |
| Malhotra Pharma Ltd | Wholesale & retail | 2025 |
| Malivu Pictures Limited | Professional & scientific | 2020 |
| Mandraki Limited | Wholesale & retail | 1998 |
| Mangmee by Naam Ltd | Health & social care | 2025 |
| Manhandy Services Ltd | Construction | 2014 |
| Mann Rentals Ltd | Administrative & support | 2021 |
| Manvell's Home Improvements Ltd | Professional & scientific | 2013 |
| Manvells Dorset Limited | Construction | 2023 |
| MAO Property Ltd | Real estate | 2025 |
| Maple Tree Engineering Limited | Professional & scientific | 2013 |
| Marble Plastering Specialists Ltd | Construction | 2023 |
| Marcabianco Ltd | Wholesale & retail | 2025 |
| Marcel Court Limited | Households | 1991 |
| March Consulting Solutions Limited | Professional & scientific | 2026 |
| Mareli Limited | Financial services | 1995 |
| Marina Place (Management) Limited | Hospitality | 2004 |
| Marine & Motorhome GAS Ltd | Administrative & support | 2025 |
| Maritime Business Centre Limited | Households | 2010 |
| Mark and Margriet Wells 2025 Limited | Financial services | 2025 |