| Lpcuk Ltd | Wholesale & retail | 2018 |
| Lperfect Holdings Ltd | Construction | 2025 |
| LPM Waste Management Ltd | Water & waste | 2021 |
| LPV Lets Ltd | Real estate | 2018 |
| LR SUB Ltd | Hospitality | 2008 |
| Lrdc Ltd | Arts & recreation | 2026 |
| LRJ Fitness Ltd | Arts & recreation | 2025 |
| Lrvtd Vzion Ltd | Wholesale & retail | 2025 |
| LS Building Swansea Ltd | Construction | 2021 |
| LS Property Swansea Ltd | Real estate | 2021 |
| LS Rentals Swansea Ltd | Real estate | 2023 |
| LSE Invest Ltd | Real estate | 2026 |
| LSL Properties Limited | Real estate | 2013 |
| LSM Holdings Ltd | Financial services | 2020 |
| Lsrh Limited | Professional & scientific | 2017 |
| LSV Water Ltd | Construction | 2018 |
| LT Media Solutions Ltd | Information & communication | 2015 |
| Ltautos Limited | Wholesale & retail | 2016 |
| Ltrad Financial Services Ltd | Financial services | 2014 |
| Luango Ltd | Information & communication | 2019 |
| Lubell Ltd | Other services | 2021 |
| Lubo Properties Ltd | Real estate | 2023 |
| Lubpon Ltd | Manufacturing | 2024 |
| Lucalu Health Limited | Health & social care | 2023 |
| Lucalu Limited | Professional & scientific | 2023 |
| Lucas Lofts Limited | Construction | 2014 |
| Lucidia Ltd | Information & communication | 2019 |
| Lucky Food 88 Limited | Hospitality | 2019 |
| Lucky Golden Limited | Hospitality | 2026 |
| Lucky Laugh Entertainment Limited | Arts & recreation | 2026 |
| Lucky Mill Properties Ltd | Real estate | 2024 |
| Lucky Numbers Entertainment Ltd | Professional & scientific | 2024 |
| Lucky Sidhu Services Ltd | Transport & logistics | 2018 |
| Luckymoneycat Limited | Hospitality | 2024 |
| Ludman Consulting Ltd | Information & communication | 2024 |
| Lugia Legends TCG Limited | Wholesale & retail | 2026 |
| Luigi & Diego Swansea Ltd | Hospitality | 2024 |
| Luke Bidder Plastering Ltd | Construction | 2024 |
| Luke Colwell Trades Ltd | Wholesale & retail | 2026 |
| LUKE0210PLATINUM Limited | Wholesale & retail | 2025 |
| Lulham Ltd. | Hospitality | 2015 |
| Lullaby's Day Nursery Limited | Health & social care | 2017 |
| Lulu Property Ltd | Real estate | 2017 |
| Lululet Ltd | Real estate | 2023 |
| Lumberjaxs Ltd | Arts & recreation | 2026 |
| Lumiere Aesthetics Limited | Other services | 2025 |
| Lumin Accountancy Ltd | Professional & scientific | 2017 |
| Lumishore Limited | Extraterritorial | 2007 |
| Luna & Crest Ltd | Education | 2013 |
| Luna 21 Ltd | Wholesale & retail | 2025 |
| Lunch Ltd | Hospitality | 2017 |
| LUNCH1 Ltd | Transport & logistics | 2023 |
| Lutic Ltd | Real estate | 2023 |
| Lutso Property Developers Ltd | Construction | 2023 |
| LUX Bar Ltd | Other services | 2016 |
| LUX Parts Sales Limited | Wholesale & retail | 2024 |
| Luxe by LM Limited | Other services | 2025 |
| Luxe Developments Swansea Limited | Real estate | 2022 |
| Luxella Ventures & Services UK Ltd | Wholesale & retail | 2025 |
| Luxeview Developments Ltd | Households | 2025 |
| Luxury UK Properties Ltd | Real estate | 2022 |
| Luxurysss Ltd | Real estate | 2025 |
| LVT Body and Paint Specialists Limited | Wholesale & retail | 2018 |
| LW Property Solutions Ltd | Construction | 2026 |
| LWH Automotives & Recovery’S Ltd | Wholesale & retail | 2026 |
| LWP and Sons Limited | Real estate | 2023 |
| Lwrs Ltd | Construction | 2026 |
| Lxtal Limited | Hospitality | 2025 |
| LYN Jones Rugby Limited | Professional & scientific | 1998 |
| Lynch Business Holdings Limited | Professional & scientific | 2025 |
| Lynch Developments Limited | Construction | 2003 |
| Lynch Property Limited | Real estate | 2008 |
| Lynch Scaffolding System Limited | Construction | 2017 |
| Lyndell House Ltd | Other services | 2004 |
| Lyntonacre Limited | Real estate | 1993 |
| M & a Pasha Construction Ltd | Construction | 2022 |
| M & D Deliveries Ltd | Transport & logistics | 2019 |
| M & G Services (Swansea) Ltd | Other services | 2010 |
| M & H Stores Ltd | Wholesale & retail | 2015 |
| M & J (Motor Repairs) Limited | Wholesale & retail | 1990 |
| M & J Woods (SW) Limited | Other services | 2017 |
| M & M`S Electrical Co. Ltd | Construction | 2009 |
| M & R Property (West Wales) Limited | Real estate | 2020 |
| M & R Roofing and Construction Limited | Construction | 2015 |
| M & S Contracting Ltd | Other services | 2025 |
| M & S Properties Swansea Ltd | Real estate | 2023 |
| M & S Williams Investments Ltd | Real estate | 2023 |
| M a Deliveries Limited | Transport & logistics | 2019 |
| M a Electrical Services Limited | Construction | 2016 |
| M a Hartley Holdings Ltd | Professional & scientific | 2016 |
| M a Homes Ltd | Real estate | 2017 |
| M a Howells Inspection Ltd | Professional & scientific | 2024 |
| M a JAY Ltd | Hospitality | 2013 |
| M and D Trading (SW) Limited | Other services | 2024 |
| M and S Cleaning Limited | Administrative & support | 2019 |
| M B H Consultancy Services Limited | Professional & scientific | 2009 |
| M C Jorgensen Deliveries Ltd | Transport & logistics | 2020 |
| M H Awad Ltd | Health & social care | 2022 |
| M Jones Carpentry and Construction Ltd | Construction | 2023 |
| M Patel & Corporation Limited | Hospitality | 2025 |