| JIM Griffiths Motor Engineering Ltd | Wholesale & retail | 2025 |
| Jjrl Auto Diagnose Limited | Wholesale & retail | 2022 |
| Jkeo Ltd | Hospitality | 2025 |
| JMI Griffiths Ltd | Health & social care | 2025 |
| JMR Fishing Limited | Agriculture & fishing | 2019 |
| John Price Specialist Joiner Ltd | Manufacturing | 2007 |
| Johnson Residential Investments Ltd | Real estate | 2025 |
| Johnston Motor Services Limited | Wholesale & retail | 2003 |
| Jomimi Ltd | Other services | 2021 |
| JON Clark Photography Limited | Construction | 2018 |
| Jones Brothers Transport Ltd | Transport & logistics | 2020 |
| Josh Ingle Carpentry Ltd | Construction | 2021 |
| Josh Owen Tree and Garden Services Ltd | Agriculture & fishing | 2023 |
| Joviperl Ltd | Administrative & support | 2023 |
| Joy for Soul Ltd | Administrative & support | 2024 |
| Joy of Live Ltd | Extraterritorial | 2025 |
| JPI Performance Ltd | Wholesale & retail | 2019 |
| JPV Design Solutions Ltd | Professional & scientific | 2022 |
| JPW Training Ltd | Professional & scientific | 2018 |
| JRP Limited | Construction | 2009 |
| JT Ndaba Ltd | Health & social care | 2014 |
| JTB R Ltd | Other services | 2019 |
| Jubilee Shellfish Co Ltd | Agriculture & fishing | 2020 |
| Julie Nicholas Limited | Other services | 2002 |
| Junaua Ltd | Extraterritorial | 2022 |
| Just Pull IT Limited | Wholesale & retail | 2014 |
| Jziaqtie Ltd | Wholesale & retail | 2023 |
| K & G Training and Consultancy Ltd | Professional & scientific | 2007 |
| K & S Griffiths Limited | Hospitality | 2017 |
| K a Perkins Limited | Professional & scientific | 2011 |
| K and M Windows (Wales) Limited | Construction | 2014 |
| K Smith Services (Pembrokeshire) Limited | Hospitality | 2012 |
| K.T Bio-Clean Services Ltd | Administrative & support | 2025 |
| K1 Barbershop Ltd | Other services | 2023 |
| Kablen Ltd | Other services | 2024 |
| Kaiyo Navis Ltd | Administrative & support | 2026 |
| Kanego Ltd | Other services | 2021 |
| Kanga Ltd | Wholesale & retail | 2025 |
| Karn Construction Ltd | Construction | 2003 |
| Kastel Ltd | Other services | 2021 |
| KAT Hummingbird Ltd. | Administrative & support | 2025 |
| Kayak King Pembrokeshire Limited | Arts & recreation | 2019 |
| KCD Hospitality Cymru Ltd | Hospitality | 2024 |
| KCS Engineering Ltd | Construction | 2010 |
| KDT Construction Ltd | Construction | 2008 |
| Kead Engineering Limited | Professional & scientific | 2012 |
| Kedgeland Ltd | Extraterritorial | 2024 |
| Keeston Hall Bungalows Management Company Limited | Households | 2005 |
| Keetprom Ltd | Other services | 2021 |
| Kelopter Ltd | Other services | 2018 |
| Kensington Gardens Residents Management Co. Limited. | Hospitality | 2005 |
| Kerpopdyl CYF | Administrative & support | 2026 |
| Kerslake Meats Ltd | Wholesale & retail | 2016 |
| Kevan Krelle Building Services Limited | Construction | 2009 |
| KEW Contracting Limited | Financial services | 2010 |
| Kfjm Holding Ltd | Financial services | 2025 |
| Kfjm Private Stiftung | Financial services | 2025 |
| Kgadfn Ltd | Administrative & support | 2025 |
| Khaki FX Tech Ltd | Manufacturing | 2023 |
| Kiln Park Limited | Construction | 2012 |
| King Groundworks Ltd | Construction | 2024 |
| Kingsland Prime Ltd | Professional & scientific | 2025 |
| Kingsmeadow Property Limited | Real estate | 2020 |
| Kiss in Sterling Silver Limited | Manufacturing | 2013 |
| KJ Prints Ltd | Wholesale & retail | 2023 |
| KL Cleaning Pembs Limited | Other services | 2016 |
| Klatium Ltd | Other services | 2018 |
| KM Professional Services Ltd | Wholesale & retail | 2023 |
| Kompass DER Freiheit Ltd | Administrative & support | 2023 |
| Kovci Ltd | Other services | 2021 |
| KP Developers (Pembs) Ltd | Construction | 2017 |
| KPR Construction Ltd | Construction | 2023 |
| Kranich Ltd | Extraterritorial | 2024 |
| Krash Kontrol T/A Readymix Ltd | Wholesale & retail | 2019 |
| Kristian K Aesthetics Training Academy Ltd | Education | 2025 |
| Kryptronic Ltd | Information & communication | 2021 |
| Krytec Mechanical Services Ltd | Professional & scientific | 2019 |
| L Jones Consulting Ltd | Professional & scientific | 2024 |
| L L Welding Services Ltd | Construction | 2015 |
| L M Griffiths & Co Limited | Professional & scientific | 2003 |
| L Rees Hospitality Limited | Hospitality | 2022 |
| L W Haggar 2 Ltd | Real estate | 2018 |
| L&C Couriers Ltd | Transport & logistics | 2025 |
| L&J Real Estate Investing Ltd | Construction | 2022 |
| L.A.M. Smith & Sons Limited | Agriculture & fishing | 2003 |
| L.J.P. Owen Limited | Other services | 2005 |
| L.Lewis Lettings Limited | Real estate | 2025 |
| L.W. Haggar & Sons Limited | Real estate | 1964 |
| Labrador Homes Limited | Construction | 2024 |
| Ladybird Wellbeing Ltd | Manufacturing | 2024 |
| Lakes Trading Company Limited | Hospitality | 2017 |
| Lamboro Farm Limited | Agriculture & fishing | 1999 |
| LAN Melin Limited | Financial services | 2020 |
| LAN YR Afon Ltd | Construction | 2026 |
| Laos Solution Ltd | Other services | 2018 |
| Laser Market LP | | 2018 |
| Lasershot Ltd | Arts & recreation | 2026 |
| Lashgari Design Group Ltd | Manufacturing | 2023 |
| Lauzon Holding PC | | 2019 |
| Lawrence Landfill Limited | Administrative & support | 2005 |