| Jonsel (Aberaeron) Ltd | Hospitality | 2021 |
| Jonsel Construction Ltd | Construction | 2023 |
| Jonsel Limited | Construction | 1996 |
| Jonsel Management Black Limited | Hospitality | 2009 |
| Jonsel Management Limited | Hospitality | 2002 |
| Joseph Bath Heating Consultancy Limited | Professional & scientific | 2022 |
| Just Desserts (Restaurants) Limited | Hospitality | 2002 |
| Karl West Media Ltd | Information & communication | 2014 |
| Khadiza Ltd | Hospitality | 2019 |
| Kinsman Residential Homes Limited | Health & social care | 2022 |
| Kirkwood & Pask Limited | Construction | 2026 |
| KLC Architects Limited | Professional & scientific | 2015 |
| Koru Architectural Limited | Professional & scientific | 2024 |
| Kriya Events Limited | Arts & recreation | 2024 |
| Kula Women Ltd | Health & social care | 2024 |
| Kurys Construction LLP | | 2010 |
| Kytonne Industries Ltd | Professional & scientific | 2026 |
| Label Ltd | Wholesale & retail | 2003 |
| Landsker Construction Limited | Construction | 2009 |
| LD24 Fitness Ltd | Arts & recreation | 2023 |
| LEE Poole and Sons Ltd. | Construction | 2010 |
| Legal Boutique & Co. Ltd | Professional & scientific | 2019 |
| Lend Engine CIC | Other services | 2024 |
| Lewis Agri Ltd | Administrative & support | 2025 |
| Lifestile Home Solutions Ltd | Construction | 2024 |
| Lili WEN Bridal Ltd | Wholesale & retail | 2020 |
| Limitless Capital Ltd | Information & communication | 2023 |
| Link Resources Limited | Professional & scientific | 1999 |
| Linquest Limited | Hospitality | 1970 |
| Lioraa London Ltd | Wholesale & retail | 2025 |
| Litterpickers.Com Ltd | Water & waste | 2022 |
| Little Pencoed Farms Limited | Agriculture & fishing | 2006 |
| LKY Ltd | Wholesale & retail | 2025 |
| Llaethdy Clôs Dairies Ltd | Wholesale & retail | 2025 |
| Llyr Evans Planning Ltd | Professional & scientific | 2014 |
| Lofi Design Ltd | Manufacturing | 2021 |
| Louise Fackrell Ltd | Hospitality | 2011 |
| Luxe Club Retreats Ltd | Professional & scientific | 2022 |
| Lynne Sacale Ltd | Professional & scientific | 2016 |
| M & C Kennedy Limited | Health & social care | 2010 |
| M & E Pearce Limited | Manufacturing | 2003 |
| M B a Precision and Marine Engineering Limited | Manufacturing | 2003 |
| M D Recycling Limited | Water & waste | 2010 |
| M D Waste & Recycling Limited | Water & waste | 2012 |
| M Everest Construction Limited | Construction | 2020 |
| M J Mullins Electrical Limited | Construction | 2022 |
| M.O. Engineering Limited | Professional & scientific | 1997 |
| Madam Limited | Wholesale & retail | 2022 |
| Madebybill Limited | Manufacturing | 2022 |
| Mamma Earth Ltd | Information & communication | 2025 |
| Mannuccis Ltd | Hospitality | 2023 |
| Mantle Brewery Limited | Manufacturing | 2011 |
| Marc L Williams Limited | Administrative & support | 2015 |
| Marian's Chippy Limited | Hospitality | 2021 |
| Mark Baggott Limited | Professional & scientific | 2003 |
| Martin Jones & SON Limited | Construction | 2006 |
| Massive Face Ltd | Arts & recreation | 2019 |
| MCJ Flooring Ltd | Construction | 2025 |
| Mediation West Wales Limited | Financial services | 2014 |
| Megan Sharkey Limited | Administrative & support | 2023 |
| Megan Van Soest Limited | Hospitality | 2015 |
| Menter Aberteifi Cyfyngedig | Administrative & support | 2001 |
| Messrs Williams Ltd | Agriculture & fishing | 2008 |
| Metal Ascent Ltd | Administrative & support | 2012 |
| Michaela Weaver Ltd | Wholesale & retail | 2020 |
| Millennium Affiliates Limited | Other services | 2019 |
| Minds MC Limited | Administrative & support | 2025 |
| More Leisure Limited | Arts & recreation | 2001 |
| Morgan & Richardson CYF | Professional & scientific | 2009 |
| Mount Sônnu Ltd | Information & communication | 2025 |
| Mountain Hall Limited | Administrative & support | 2013 |
| Mundos Ltd | Wholesale & retail | 2007 |
| Myrtle Properties Limited | Wholesale & retail | 1999 |
| N & M Solutions Limited | Financial services | 2008 |
| N C Baker Ltd | Financial services | 2009 |
| Nant Developments Limited | Real estate | 2022 |
| National Sealants Limited | Construction | 2015 |
| Naturally Morocco Limited | Administrative & support | 1996 |
| Naturewise Community Forest Garden C.I.C. | Agriculture & fishing | 2017 |
| Naturewise Eco Shop CIC | Wholesale & retail | 2019 |
| Neil Jones Kitchens Limited | Construction | 2021 |
| Nerys Richards Ltd | Arts & recreation | 2010 |
| Netring Limited | Information & communication | 2003 |
| Nevarlo Ltd | Hospitality | 2022 |
| New Life Community Projects | Wholesale & retail | 2004 |
| Newera Metal Resources Ltd | Administrative & support | 2016 |
| Norman Holdings (West Wales) Limited | Mining & quarrying | 2021 |
| Northern Lights Construction Limited | Construction | 2025 |
| Noyadd Trefawr Residents Association Limited | Real estate | 2013 |
| NRC Solutions Limited | Construction | 2007 |
| Ny's Foods Chinese Takeaway Limited | Hospitality | 2025 |
| Ny's Nails Lush Limited | Other services | 2026 |
| O C Davies & SON Limited | Wholesale & retail | 2004 |
| O M Davies & Sons Limited | Agriculture & fishing | 2009 |
| Oaots Limited | Construction | 2014 |
| Ocean Sea Products Limited | Wholesale & retail | 2025 |
| Oemttparts Ltd | Wholesale & retail | 2025 |
| OMS Cardigan Limited | Administrative & support | 2025 |
| Oojudoo (Cardigan) Limited | Other services | 2019 |
| Oojufink Limited | Other services | 2007 |