| Lakeside Window Systems Ltd | Manufacturing | 2002 |
| Lamdud Limited | Transport & logistics | 2016 |
| Lamont Building Ltd | Construction | 2021 |
| Lamp Design Limited | Information & communication | 2005 |
| Lamps Venue Limited | Hospitality | 2021 |
| LAN Associates (UK) Limited | Professional & scientific | 2006 |
| Lancet Holdings Limited | Hospitality | 2023 |
| Lanco Safewear Sourcing Limited | Financial services | 2019 |
| Land Enhancement Services Limited | Real estate | 2009 |
| Landed Futures Community Interest Company | Professional & scientific | 2025 |
| Landlords in Wales Ltd | Information & communication | 2024 |
| Landmark Asset Group Ltd | Real estate | 2026 |
| Landmark Education Ltd | Financial services | 2025 |
| Landsker Limited | Mining & quarrying | 2004 |
| Langcliffe Park Residents Ltd | Energy | 2013 |
| Langland Bay Developments Limited | Real estate | 1939 |
| Langland Bay Golf Club Limited, | Arts & recreation | 1927 |
| Langland Bay Holdings Limited | Financial services | 2022 |
| Langland Bay Manor Management Limited | Real estate | 2007 |
| Langland Bay Property Limited | Real estate | 2019 |
| Langland Cleaning Solutions Ltd | Other services | 2019 |
| Langland Consulting Limited | Professional & scientific | 2021 |
| Langland Court Developments Limited | Hospitality | 1984 |
| Langland Cove Limited | Administrative & support | 2014 |
| Langland Radiology Limited | Health & social care | 2024 |
| Langland Testing House Ltd | Professional & scientific | 2024 |
| Langstone Supplies Limited | Wholesale & retail | 2013 |
| Lanlola Limited | Wholesale & retail | 2025 |
| Lanshew Cables & Accessories Limited | Wholesale & retail | 2016 |
| Lapfix Ltd | Information & communication | 2010 |
| Lara Johnson Lifestyle Ltd | Other services | 2001 |
| Larvot.To Limited | Information & communication | 2019 |
| Lashy Nova Limited | Other services | 2025 |
| Latch Recruitment Limited | Administrative & support | 2024 |
| Late December Films Ltd | Information & communication | 2018 |
| Latitude Clothing Ltd | Wholesale & retail | 2026 |
| Latus Trading Co. Limited | Wholesale & retail | 2025 |
| Laugharne Morgan Limited | Wholesale & retail | 2019 |
| Launch Brickwork Limited | Construction | 2006 |
| Launch One Ltd | Wholesale & retail | 2026 |
| Laundry Hub & Services Ltd | Other services | 2025 |
| Laundry Lounge Service Limited | Other services | 2026 |
| Laundry Room (Swansea) Limited | Extraterritorial | 2015 |
| Laura Blume Ltd | Administrative & support | 2019 |
| Lauralisa Properties Ltd | Real estate | 2022 |
| Lauren Amelia Atelier Ltd | Wholesale & retail | 2025 |
| Lauren Amelia Ltd | Professional & scientific | 2022 |
| Laurence Ellis Marine Consultants Limited | Professional & scientific | 2022 |
| Laurence Evans Properies Ltd | Real estate | 2017 |
| Lavender Sweep Records Ltd | Information & communication | 2019 |
| Lawes & Co Marine Consultants Limited | Professional & scientific | 2014 |
| Lawmen Barbers Ltd | Other services | 2021 |
| Lawrence Hand Surgery Limited | Health & social care | 2025 |
| Laws Property Limited | Real estate | 2014 |
| Lawson Finance Co. | Real estate | 1958 |
| Layco Flooring Solutions Limited | Construction | 2026 |
| Layla Grace Homes Limited | Real estate | 2024 |
| Layton Lewis Technical Services Limited | Professional & scientific | 2024 |
| Lazza's Lettings Limited | Real estate | 2021 |
| LB Car Sales Limited | Wholesale & retail | 2014 |
| LB Union Enterprises Ltd | Hospitality | 2020 |
| Lbaspv Ltd | Real estate | 2026 |
| LBC Hospitality and Consultancy Ltd | Professional & scientific | 2024 |
| LBF Developments Ltd | Real estate | 2025 |
| LBH Construction Limited | Construction | 2017 |
| LC Kitchens & Interiors Ltd | Wholesale & retail | 2020 |
| LC Litho Print Ltd | Manufacturing | 2024 |
| LC Print and Digital Ltd | Manufacturing | 2024 |
| LCD Enterprises Limited | Professional & scientific | 1994 |
| LCJ Property Ltd | Real estate | 2020 |
| LCJ Retail Ltd | Wholesale & retail | 2022 |
| LCR Retail Group Ltd | Wholesale & retail | 2025 |
| LD DRY Lining Limited | Construction | 2016 |
| LDL Foods Ltd | Hospitality | 2015 |
| LDL Quantity Surveyors Ltd | Professional & scientific | 2024 |
| LDS Building Group Ltd | Construction | 2025 |
| LE Dossier Francais Ltd | Other services | 2010 |
| LE Petit Four Limited | Hospitality | 2006 |
| LE Temp Contractors Limited | Administrative & support | 2014 |
| LE Temp Permanents Limited | Administrative & support | 2014 |
| Lead FOX Ltd | Professional & scientific | 2018 |
| LEADGENERATION247.ONLINE Limited | Professional & scientific | 2020 |
| Leading Magnetic Design Ltd | Manufacturing | 2008 |
| Leaf Kitchens and Bedrooms Ltd | Wholesale & retail | 2017 |
| Leah RHE Dance Company Ltd | Arts & recreation | 2024 |
| Leak Fixers Swansea Plumbing Ltd | Construction | 2025 |
| Lean Manufacturing Excellence Ltd | Professional & scientific | 2014 |
| Leap to Learn Ltd | Education | 2009 |
| Leapfrog Advertising Ltd | Professional & scientific | 2025 |
| Leapgold Limited | Real estate | 1997 |
| Learn and Earn Training Ltd | Education | 2021 |
| Learn With SMW Ltd | Education | 2022 |
| Learncyber Ltd | Information & communication | 2026 |
| Lease Extension Experts Limited | Professional & scientific | 2022 |
| Lease From US Ltd | Real estate | 2019 |
| Lease.It Own.It Ltd | Wholesale & retail | 2016 |
| Leather Sofa Company Limited | Wholesale & retail | 2003 |
| Leati Media Limited | Information & communication | 2026 |
| LEC Llanelli Limited | Arts & recreation | 2010 |
| Leckonby Engineering Ltd | Manufacturing | 2017 |