| Lotus Garden Takeaway Limited | Hospitality | 2022 |
| LSU: Love, Support, Unite Africa Ltd | Wholesale & retail | 2013 |
| Luke Fleming Fighting Limited | Arts & recreation | 2026 |
| Madden Capital Limited | Real estate | 2025 |
| Maitland MON Ltd | Real estate | 2017 |
| Makerfield Property Investments Limited | Financial services | 1964 |
| Management & Enterprise Training Limited | Professional & scientific | 2013 |
| Marina Stores and Cafe Bar (Holyhead) Ltd | Hospitality | 2025 |
| Marine Lodge Ltd | Hospitality | 2019 |
| Market Hotel Llangefni Limited | Hospitality | 2022 |
| Mayo MPW Ltd | Households | 2023 |
| MC Williams Building Contractors Limited | Construction | 2022 |
| Mcginn Offshore Ltd | Professional & scientific | 2024 |
| Mckernon & Williams Projects Limited | Administrative & support | 2024 |
| MCN Cleaning Solutions Ltd | Administrative & support | 2024 |
| MD2 Developments Ltd | Construction | 2025 |
| ME Property Holdings NW Ltd | Real estate | 2026 |
| Medra Properties Ltd | Real estate | 2026 |
| Megan Valerie Photography Ltd | Professional & scientific | 2022 |
| Mike Sierra Holdings Limited | Financial services | 2025 |
| Minesto UK Limited | Manufacturing | 1996 |
| Minhan Trading Limited | Wholesale & retail | 2026 |
| Mjhair Limited | Other services | 2026 |
| Moduron Maethlu (Motors) Limited | Transport & logistics | 1982 |
| Moffett Ltd | Wholesale & retail | 2023 |
| MON Civils Limited | Construction | 2023 |
| MON Fire Management Ltd | Public administration | 2012 |
| MON Geomatics Ltd | Professional & scientific | 2026 |
| MON Maintenance Services Limited | Professional & scientific | 2009 |
| MON Medics Ltd | Health & social care | 2023 |
| MON Safety Services Ltd | Professional & scientific | 2019 |
| Mona Aviation Limited | Arts & recreation | 1975 |
| Mona Classics Limited | Manufacturing | 2020 |
| Mona Fuel and Trading Company Limited | Manufacturing | 1964 |
| MOR Awelon and London Road Community Regeneration Partnership | Health & social care | 2001 |
| My Learning Voice Ltd | Education | 2026 |
| Mynachdy Farms Limited | Financial services | 2014 |
| MÔN Tooling Limited | Manufacturing | 2022 |
| Naja Reptile Courier Ltd | Transport & logistics | 2021 |
| Naked Floors Ltd | Wholesale & retail | 2005 |
| Naughty Nibbles Limited | Hospitality | 2023 |
| Navigator Marine Ltd | Professional & scientific | 2023 |
| Neillrhos Ltd | Real estate | 2025 |
| Network Consult Limited | Information & communication | 2021 |
| Network Logistics Ltd | Other services | 2019 |
| Newry Store Ltd | Wholesale & retail | 2021 |
| Nextgen Trace Ltd | Information & communication | 2026 |
| NJM Engineering Surveyors Ltd | Construction | 2025 |
| NK Training and Consultancy Ltd | Education | 2023 |
| North Wales Industrial Roofing Ltd | Construction | 2023 |
| North Wales Sanitary Cladding Ltd | Construction | 2016 |
| Northwales Taverns Ltd | Hospitality | 2024 |
| NW Mobile Phones Limited | Wholesale & retail | 2025 |
| O. G. Owen Ltd | Transport & logistics | 2016 |
| O.R.Jones & Sons Limited | Wholesale & retail | 1962 |
| Ocean Bay Seafoods Limited | Wholesale & retail | 2012 |
| Optimal Edge Coaching Ltd | Financial services | 2020 |
| OS Business Solutions Ltd | Information & communication | 2010 |
| Outdoor Alternative Ltd | Hospitality | 2021 |
| Owen Planning Services UK Limited | Professional & scientific | 2023 |
| Padog Enterprises Limited | Agriculture & fishing | 2014 |
| Parkinson Plumbing and Heating Ltd | Construction | 2026 |
| Parquet Floors Limited | Manufacturing | 2006 |
| Parry Power Utilities Limited | Construction | 2023 |
| Partneriaeth Cymunedol Porthfelin CYF | Health & social care | 2003 |
| Paul COX Marine Limited | Manufacturing | 2013 |
| Pencraig Campsite Limited | Hospitality | 2024 |
| Pengwran Investment Enterprises Ltd | Real estate | 2025 |
| Penrhos Community Nature Reserve CIC | Arts & recreation | 2026 |
| Penrhos Truck Stop Limited | Transport & logistics | 2021 |
| Peregrine Education Consulting Limited | Education | 2023 |
| Peter Richardsons Estates North Wales Ltd | Real estate | 2023 |
| Phoenix Leading Business Solutions Ltd | Other services | 2018 |
| Pioneer Courtyard Apartments Ltd | Hospitality | 2025 |
| Piranha Bars Limited | Hospitality | 2013 |
| PJ Property Services at the Boathouse Limited | Hospitality | 2026 |
| Plas Llanfair Limited | Agriculture & fishing | 2019 |
| Plas Newydd Ltd | Agriculture & fishing | 2020 |
| Platinum PHW Ltd | Real estate | 2019 |
| Pro Tint Window Films Ltd | Manufacturing | 2026 |
| Probability One Limited | Education | 2000 |
| Professional Touch Painting and Decorating Ltd | Construction | 2021 |
| Puleston Publishing Ltd | Arts & recreation | 2014 |
| Pure Design INT Limited | Manufacturing | 2016 |
| Quack Sourcing Ltd | Administrative & support | 2025 |
| R G Hire Ltd | Construction | 2008 |
| R Mills, Daughter & SON Ltd | Construction | 2005 |
| Raja's Bengali Cuisine & Holyhead Inn Limited | Hospitality | 2025 |
| Rasul Turkish Barber Ltd | Other services | 2023 |
| RC Living Spaces Ltd | Real estate | 2025 |
| Readyblinds Ltd | Manufacturing | 2023 |
| Red Square Developments Ltd | Construction | 2021 |
| Redstart Publishing Limited | Information & communication | 2015 |
| Resource Renew Ltd | Wholesale & retail | 2013 |
| Retrobox Ltd | Other services | 2025 |
| Revpaws Ltd | Wholesale & retail | 2024 |
| Rhosneigr Stores Ltd | Hospitality | 2025 |
| RIC Engineering Limited | Manufacturing | 2016 |
| RIC Holdings & Developments Limited | Financial services | 2024 |
| Robmac Holdings Limited | Professional & scientific | 2010 |