| M & R Scaffolding Ltd | Construction | 2013 |
| M and R S Bodrida Ltd | Agriculture & fishing | 2023 |
| M G Roberts CYF | Agriculture & fishing | 2018 |
| M Rimmer Property Limited | Real estate | 2024 |
| M&G Vaughan CYF | Administrative & support | 2025 |
| Madoc Propertys Limited | Real estate | 2022 |
| Madoc Yacht Club Ltd | Arts & recreation | 2005 |
| Madog Cleaners Ltd | Other services | 2016 |
| Madog POP UP Fitness Spin CYF | Arts & recreation | 2025 |
| Madog SBA Ltd | Health & social care | 2025 |
| Mark Pilkington Golf Limited | Arts & recreation | 2022 |
| Maybank Renovation Building & Joinery Services Ltd | Construction | 2024 |
| Maybank Renovation Limited | Construction | 2010 |
| Meddyg Care (Criccieth) Ltd | Health & social care | 2018 |
| Meddyg Care (Facilities Management) Ltd | Construction | 2022 |
| Meddyg Care (Help at Home) Ltd. | Health & social care | 2019 |
| Meddyg Care (Porthmadog) Ltd | Health & social care | 2016 |
| Meddyg Care (Rhyl) Limited | Health & social care | 2009 |
| Meddyg Care (Y Felinheli) Ltd | Health & social care | 2024 |
| Meddyg Care Group Holdings Ltd | Transport & logistics | 2001 |
| Meicro CYF | Information & communication | 2021 |
| Meithrinfa Blagur CYF | Health & social care | 2013 |
| Meithrinfa HEN Ysgol CYF | Health & social care | 2015 |
| Menai Mussels Limited | Agriculture & fishing | 2015 |
| Mentro Developments Limited | Real estate | 2008 |
| Mentro MOR a Mynydd (UP4IT Outdoors) CYF | Arts & recreation | 2005 |
| Mike's Garage (Llandygai) Ltd | Wholesale & retail | 2014 |
| Milfeddygon Deufor CYF | Professional & scientific | 2017 |
| MIN - Y - MOR Hotel Ltd | Hospitality | 2016 |
| Minalar Limited | Real estate | 2013 |
| Modular Build Solutions Ltd | Construction | 2017 |
| Moduron H G Jones Motors Limited | Wholesale & retail | 2011 |
| Moel Geifr CYF | Agriculture & fishing | 2016 |
| Moelfre Hydro Limited | Energy | 2014 |
| Mooney 64 Limited | Real estate | 2022 |
| Mooney Caravan Sales Limited | Other services | 2018 |
| Moonflower Holdings Ltd. | Financial services | 2014 |
| Moonflower Investments 2 Ltd | Real estate | 2019 |
| Morfa Mawr Camping CYF | Hospitality | 2021 |
| Musker Limited | Agriculture & fishing | 2002 |
| MW Living Limited | Real estate | 2021 |
| My Leather Manbag Ltd | Wholesale & retail | 2013 |
| Mynydd DU Caravan Park Limited | Hospitality | 2017 |
| ND Matera Limited | Real estate | 2018 |
| Neud Ltd | Manufacturing | 2023 |
| Nikolaos Papageorgiou Ltd | Health & social care | 2017 |
| Nofain CYF | Administrative & support | 2024 |
| North Wales Slate and Stone Ltd | Manufacturing | 2013 |
| North Wales Van Hire Ltd | Administrative & support | 2025 |
| North West Labour Force Ltd | Extraterritorial | 2016 |
| North West Wales Electrical Ltd | Construction | 2022 |
| Northern Welsh Quarries Ltd | Mining & quarrying | 2014 |
| Northern Welsh Recycling Ltd | Water & waste | 2015 |
| O D Roberts CYF | Agriculture & fishing | 2018 |
| O J Jones & SON Limited | Transport & logistics | 2006 |
| O Law I Law CYF | Health & social care | 2021 |
| O R Electrical Limited | Construction | 2017 |
| O R Properties Ltd | Real estate | 2018 |
| OD Jones Beaumaris CYF | Agriculture & fishing | 2017 |
| OFF the Bench Ltd. | Administrative & support | 2020 |
| OIL Heating Gwynedd (OHG) Limited | Households | 2016 |
| Oldfield Logistics Ltd | Transport & logistics | 2017 |
| ON the Shore Limited | Hospitality | 2014 |
| Orange Cube Ltd | Real estate | 2020 |
| Owen David Limited | Real estate | 2017 |
| P & M Property Group Ltd | Real estate | 2024 |
| P E Hospitality Ltd | Hospitality | 2025 |
| P. B. Joinery Specialist Limited | Construction | 2014 |
| PA Property Group Ltd | Real estate | 2025 |
| Panadda Ltd | Hospitality | 2025 |
| Paniq Rooms Ltd | Arts & recreation | 2020 |
| Pant Y Saer Caravan Park Ltd | Hospitality | 2025 |
| Parc Wernol CYF | Hospitality | 2016 |
| Paul Valentine T/A Valco Limited | Wholesale & retail | 2010 |
| Pearson & Co Tree Services Ltd | Administrative & support | 2019 |
| Peirianwaith Eifionydd Engineering Ltd | Manufacturing | 2018 |
| PEN Y Bont (Rheolaeth) Ltd | Households | 2016 |
| Penbryn Caravan Site Ltd | Hospitality | 2024 |
| Pending Press Ltd. | Wholesale & retail | 1999 |
| Penhelyg Limited | Households | 1975 |
| Pennant Plant Ltd | Administrative & support | 2019 |
| Perthi Beddgelert CYF | Hospitality | 2017 |
| Pharmacovigilance Consultancy Services Limited | Professional & scientific | 2025 |
| Phones & Repair Hub Ltd | Wholesale & retail | 2023 |
| PLAN4HEALTH Ltd | Health & social care | 2024 |
| Plas Contracting Limited | Agriculture & fishing | 2012 |
| Pods Pwll Coch CYF | Hospitality | 2020 |
| Point Lynas Caravan Park Ltd | Hospitality | 2025 |
| Porthmadog Golf Club Limited | Arts & recreation | 2015 |
| Porthmadog Kebab Ltd | Hospitality | 2021 |
| Porthmadog NO1 Hand Car Wash Ltd | Administrative & support | 2026 |
| Portmadoc Holiday Camp Limited | Hospitality | 1964 |
| Positive Ageing Consultancy & Training Ltd | Health & social care | 2023 |
| Promote Capital Limited | Real estate | 2017 |
| Purple Moose Brewery Ltd | Manufacturing | 2002 |
| Quasar Assets Ltd | Hospitality | 2021 |
| R H Evans Cyfyngedig | Wholesale & retail | 2007 |
| R Humphreys & Sons Ltd | Construction | 2008 |
| R J Jones Plumbing & Heating Ltd | Construction | 2021 |
| R.L. Davies (Plant Hire) Limited | Administrative & support | 2005 |