| JLP Properties LLP | | 2008 |
| JMB1 Ltd | Professional & scientific | 2025 |
| JMS Deliveries Ltd | Transport & logistics | 2024 |
| Jnlb Properties Ltd | Real estate | 2021 |
| John Evans Associates Limited | Professional & scientific | 2021 |
| Jolly Holdings Limited | Administrative & support | 2021 |
| Jones & Bartlett Accountants Ltd | Professional & scientific | 2023 |
| Jones & Haley Investments Ltd | Real estate | 2021 |
| Joy Hair Studios Limited | Other services | 2026 |
| JRS Scrap Metal Ltd | Wholesale & retail | 2025 |
| JSM Energy Solutions Ltd | Manufacturing | 2025 |
| Jtim Living Ltd | Real estate | 2025 |
| Julia Jones Limited | Wholesale & retail | 2002 |
| Juno Housing Ltd | Real estate | 2021 |
| Just Bounce NW Ltd | Arts & recreation | 2025 |
| Just Genius Limited | Professional & scientific | 2021 |
| Justkate Limited | Hospitality | 2020 |
| K O Classics Ltd | Wholesale & retail | 2026 |
| K&C Cleaning and Property Management Ltd | Administrative & support | 2025 |
| K&Za Services Ltd | Transport & logistics | 2024 |
| K-Ibex Occupational Health Ltd | Health & social care | 2025 |
| K.S.2 Limited | Construction | 2002 |
| Kalco Consulting Ltd | Professional & scientific | 2018 |
| Kamaya Painters Limited | Construction | 2003 |
| Katie Birkett Ltd | Administrative & support | 2025 |
| Katie Knox Limited | Administrative & support | 2011 |
| Keane-Enterprise Ltd | Wholesale & retail | 2025 |
| Kerala Cafe and Currys Ltd | Hospitality | 2025 |
| Kerb Appeal NW Ltd | Administrative & support | 2024 |
| Kevadamson.Com Ltd | Professional & scientific | 2013 |
| Kevin Simm Music Limited | Professional & scientific | 2011 |
| Kick IT Sports Enterprise C.I.C. | Education | 2024 |
| Kimor Recruitment Limited | Administrative & support | 2020 |
| Knexgen Limited | Information & communication | 2017 |
| Knexgen Technologies Limited | Wholesale & retail | 2020 |
| Knox Insolvency Limited | Professional & scientific | 2010 |
| Koland Limited | Construction | 2025 |
| Krixm Ltd | Wholesale & retail | 2025 |
| Kruzheva Limited | Construction | 2025 |
| Kurtis Chapman Ltd | Construction | 2014 |
| L & N Palladium Complete Bathrooms Ltd | Construction | 2024 |
| L C Hotels Limited | Hospitality | 2014 |
| L Pearce Home Improvements Ltd | Construction | 2020 |
| L&H Cars Limited | Wholesale & retail | 2024 |
| L&L Miller Property Management Ltd | Real estate | 2023 |
| L&S VP Limited | Real estate | 2022 |
| Lake Press (UK) PTY Limited | Information & communication | 2026 |
| Lambert's Memorial Masons Ltd | Other services | 2023 |
| LAO Beauty Ltd | Real estate | 2021 |
| Larkfield Property Management Limited | Real estate | 2021 |
| Laser Pure Surface Restoration Limited | Other services | 2025 |
| Lauriston Court Hotel Limited | Hospitality | 2011 |
| Lawn Medic Limited | Administrative & support | 2012 |
| Lawton Court Limited | Hospitality | 2014 |
| Layhot Limited | Construction | 2025 |
| LE Sport Health & Fitness Limited | Arts & recreation | 2004 |
| Lead Bay Properties Ltd | Real estate | 2025 |
| Lema Home Improvements Ltd | Construction | 2026 |
| Lemon Cove Limited | Real estate | 2025 |
| Lesley Singleton Ltd | Health & social care | 2021 |
| Lewis Family Ministries | Other services | 2024 |
| Lexia Limited | Other services | 2016 |
| Leyland Wine Limited | Wholesale & retail | 2011 |
| LGF Consulting Ltd | Information & communication | 2012 |
| Libero Inventory Management Ltd | Professional & scientific | 2015 |
| Life and Harvest Limited | Other services | 2023 |
| Lilly HUE Nail Salon Ltd | Other services | 2023 |
| Limalima Ltd | Wholesale & retail | 2015 |
| Limivex Marketing Consultants Ltd | Professional & scientific | 2023 |
| Line Caught Sea Bass Ltd | Agriculture & fishing | 2020 |
| Line Maintenance Contracting Ltd | Other services | 1998 |
| Link International Innovation (Llandudno) | Administrative & support | 2011 |
| Little Munchkins Efail Isaf Ltd | Health & social care | 2018 |
| Little Wren Cottages Ltd | Hospitality | 2025 |
| LJ Care Link Ltd | Information & communication | 2025 |
| Llanbrighton Bridge Union CYF | Other services | 2024 |
| Llandudno & District Bridge Club Limited | Arts & recreation | 1951 |
| Llandudno Gardening Limited | Administrative & support | 2025 |
| Llandudno Holiday Properties Limited | Real estate | 2021 |
| Llandudno Properties Ltd | Real estate | 2021 |
| Llanelian Community Association CYF. | Other services | 2023 |
| Lleweni Management Company Limited | Households | 2006 |
| Llindir Farms Ltd | Agriculture & fishing | 2020 |
| Lloyd Street (Llandudno) Management Limited | Real estate | 2004 |
| Llwyn Contractors Ltd | Extraterritorial | 2024 |
| Llwyn Landscapes Ltd | Administrative & support | 2015 |
| Llys Afon Management Ltd | Households | 2023 |
| Llys Marl Management Company Limited | Households | 2018 |
| Lock Boxx Ltd | Transport & logistics | 2025 |
| Lococo Limited | Professional & scientific | 2017 |
| Locomotors Ltd | Wholesale & retail | 2026 |
| Longridge Management Limited | Households | 2014 |
| Looney Ltd | Arts & recreation | 2023 |
| Lopez & Moreno Ltd | Health & social care | 2013 |
| Louis.M Propertys Ltd | Real estate | 2021 |
| LSM Healthcare Ltd | Health & social care | 2024 |
| Ltaj Services Limited | Health & social care | 2013 |
| Luke Roberts Media Ltd | Arts & recreation | 2023 |
| Luminix Technologies Limited | Wholesale & retail | 2023 |
| Luxury Lifestyles Concierge Ltd | Other services | 2023 |