| Llewellyn Rhys Construction Ltd | Construction | 2025 |
| Llewellyn Rhys Estates Ltd | Real estate | 2026 |
| Llewellyn Roberts Ltd | Hospitality | 2021 |
| Lliswerry Llizards FC CIC | Arts & recreation | 2022 |
| Lloyd LED SAX Limited | Arts & recreation | 2026 |
| Llyr Developments Ltd | Real estate | 2021 |
| Llys Ffynnon (Phase 2) Management Company Limited | Real estate | 2005 |
| Llys Meddyg Holdings Ltd | Financial services | 2017 |
| Llys Meddyg Ltd | Hospitality | 2017 |
| LM Care Consultancy Ltd | Professional & scientific | 2025 |
| LM Equestrian Limited | Wholesale & retail | 2023 |
| LM Haulage Ltd | Transport & logistics | 2025 |
| Lmedical Ltd | Administrative & support | 2025 |
| LMG Psychology Limited | Health & social care | 2024 |
| LMJ Property Group Limited | Real estate | 2024 |
| LMT Pipeworks Ltd | Manufacturing | 2013 |
| LNS Business Services Limited | Professional & scientific | 2013 |
| LO Properties Limited | Real estate | 2018 |
| LOA Twins Ltd | Education | 2018 |
| Loamin Limited | Professional & scientific | 2022 |
| LOC Electrics Cardiff Ltd | Other services | 2015 |
| Local Heating Group Limited | Arts & recreation | 2010 |
| Local Link Community Magazine Ltd | Extraterritorial | 2016 |
| Local Projects & Developments Limited | Professional & scientific | 2025 |
| Localtradesuk Ltd | Construction | 2022 |
| Lochen Investment Ltd | Real estate | 2025 |
| Lochside Creative Ltd | Professional & scientific | 2026 |
| Lockfit (Isle of Wight) Ltd | Other services | 2023 |
| Lodgeway Properties Ltd | Real estate | 2017 |
| Loft Properties Limited | Construction | 2018 |
| Loft South Wales Ltd | Construction | 2016 |
| Lofttec Lofts Ltd | Construction | 2020 |
| Logic Building Services Limited | Construction | 2015 |
| Logicon Automation Ltd | Professional & scientific | 2011 |
| Logitech Electronics Holdings Limited | Financial services | 2011 |
| Logitech Electronics Limited | Manufacturing | 1985 |
| Logitech Investments Limited | Financial services | 2019 |
| Loglo Technologies Ltd | Professional & scientific | 2025 |
| Logo IT UK Ltd | Extraterritorial | 2019 |
| Logree Developments Ltd | Construction | 2020 |
| LOKATOR21 Limited | Construction | 2019 |
| Lolland Ltd | Professional & scientific | 2020 |
| Lombre Beauty Academy Ltd | Education | 2021 |
| London Retreats Limited | Other services | 1993 |
| London Study Express Ltd | Professional & scientific | 2023 |
| Lone Worker Guardian Limited | Information & communication | 2016 |
| Lonergan RCS Ltd | Construction | 2019 |
| Lonfeed Limited | Professional & scientific | 2015 |
| Long Lane Carpets and Flooring Limited | Wholesale & retail | 2015 |
| Long Orchard Management Limited | Households | 2007 |
| Longcourt Cottage Ltd | Hospitality | 2020 |
| Longer Technology Ltd | Information & communication | 2024 |
| Longford Properties Limited | Real estate | 1983 |
| Longmore Construction Limited | Construction | 2020 |
| Longview Advisory Services Ltd | Professional & scientific | 2018 |
| Lonsdale Psychology Services Ltd | Health & social care | 2026 |
| Lonsdale Vehicle Sales Direct Limited | Wholesale & retail | 2013 |
| Look UP Productions Ltd | Professional & scientific | 2023 |
| Lookline Limited | Wholesale & retail | 2026 |
| Loosehead Labs Ltd | Information & communication | 2026 |
| Lorann Engineering Limited | Manufacturing | 2010 |
| Lord & Lady K Limited | Other services | 2025 |
| Loresense Ltd | Wholesale & retail | 2026 |
| Lorry Park (Newport) Ltd | Transport & logistics | 2020 |
| LOS Reyes Tapas Limited | Hospitality | 2019 |
| Lost in the Source Ltd | Wholesale & retail | 2022 |
| Lost Soul Tattoo Studio Ltd | Arts & recreation | 2025 |
| Loud Llama Ltd | Professional & scientific | 2020 |
| Loudoun House Management Company Limited | Households | 1996 |
| Loukris Limited | Hospitality | 2023 |
| Lourg Healthcare Ltd | Health & social care | 2016 |
| Lousim Limited | Hospitality | 2025 |
| Love Coding Limited | Information & communication | 2013 |
| Love Housing Limited | Real estate | 2022 |
| Love Running Limited | Wholesale & retail | 2010 |
| Love Technologies Ltd | Professional & scientific | 2013 |
| Love the Student Limited | Wholesale & retail | 2019 |
| Loved & Recycled Ltd | Wholesale & retail | 2026 |
| Loved Studios Ltd | Information & communication | 2023 |
| Lovel Estates Limited | Real estate | 2020 |
| Lovell Home Improvements Ltd | Construction | 2019 |
| Lovell Project Management Ltd | Construction | 2011 |
| Lovely Jubbly Bakes Limited | Manufacturing | 2025 |
| Lover's Football Club Ltd | Wholesale & retail | 2021 |
| LOW Zero Carbon Consultants Ltd | Professional & scientific | 2022 |
| Lower Dock Holdings Ltd | Real estate | 2024 |
| Lower Talland Limited | Households | 2010 |
| Loyal Blue Recruitment Ltd | Administrative & support | 2024 |
| Loyalty Arts & Development CIC | Arts & recreation | 2025 |
| Loyalty Arts Limited | Arts & recreation | 2021 |
| LPA Solutions Ltd | Public administration | 2025 |
| LPR Holdings Ltd | Financial services | 2023 |
| LR Educational Psychology Services Limited | Education | 2023 |
| LRC Site Services Ltd | Professional & scientific | 2025 |
| LRE Distrubutions Ltd | Wholesale & retail | 2025 |
| LRJ Carpentry Ltd | Manufacturing | 2022 |
| LRJ Planning Ltd | Professional & scientific | 2016 |
| LRZ Limited | Arts & recreation | 2021 |
| LS Developments (Shropshire) Ltd | Construction | 2019 |
| LS Nails Spa Ltd | Other services | 2026 |