| Neef Teef Ltd | Health & social care | 2013 |
| Neil Fenn Urology Ltd | Health & social care | 2018 |
| Neptune Manpower Limited | Manufacturing | 2013 |
| Netzero Semiconductors Limited | Professional & scientific | 2021 |
| Newwave Custom Conversions Ltd | Wholesale & retail | 2019 |
| NG Wines Limited | Wholesale & retail | 2016 |
| Nicola J Wilkes Ltd | Professional & scientific | 2012 |
| Nightingale Investment Management Limited | Agriculture & fishing | 2016 |
| Novactus Limited | Professional & scientific | 2015 |
| NST Management & Development Ltd | Administrative & support | 2013 |
| NTG Gymnastics Ltd | Arts & recreation | 2018 |
| Nutriju Limited | Wholesale & retail | 2023 |
| Nwcc Property Ltd | Administrative & support | 2019 |
| O&N Wealth Limited | Financial services | 2008 |
| O. Bartlett Massage Therapy Ltd | Health & social care | 2025 |
| O. Bartlett Strength Therapy Ltd | Health & social care | 2024 |
| Oak Priory Properties Limited | Households | 2022 |
| Oakley Rentals Ltd | Real estate | 2020 |
| OBI Camping & Leisure Limited | Wholesale & retail | 2007 |
| Ocean House Properties Limited | Real estate | 2023 |
| Ocean Park Management Limited | Real estate | 1989 |
| Oceantec Limited | Wholesale & retail | 2013 |
| OEM Frames Limited | Manufacturing | 2017 |
| OEM Upholstery Limited | Manufacturing | 2017 |
| OFF Grid Engineering Ltd | Construction | 2020 |
| Offerson Limited | Health & social care | 2020 |
| Official Fitness Ltd | Education | 2023 |
| OIL Facilities Limited | Water & waste | 2007 |
| Old Cowbridge Grammar School Management Company Limited | Real estate | 2007 |
| Olding Construction Limited | Construction | 2023 |
| Olive Orthopaedics Limited | Health & social care | 2022 |
| ON Site Leasing Limited | Administrative & support | 2026 |
| ON Site Repairs and Maintenance Ltd | Manufacturing | 2024 |
| One Retail Developments Ltd | Construction | 2018 |
| Open Space Creative Limited | Administrative & support | 2004 |
| Opfi Ltd | Administrative & support | 2022 |
| Orchard Media Properties Ltd | Real estate | 2014 |
| Orecchiette Limited | Hospitality | 2011 |
| Orinoco Property Ltd | Real estate | 2015 |
| Orla Adams Limited | Education | 2024 |
| OUR Forever Angels CIC | Health & social care | 2023 |
| P Sullivan Carpentry Limited | Construction | 2003 |
| P.A. Stockton Brickwork Contractors Limited | Construction | 2001 |
| Pact Holds Limited | Manufacturing | 2026 |
| Page 72 Ltd | Professional & scientific | 2012 |
| Page by Page Ltd | Information & communication | 2019 |
| Parety Ltd | Information & communication | 2023 |
| Paritas Legal Limited | Administrative & support | 2020 |
| Pauletts Workshops Limited | Real estate | 1996 |
| Pbcs Aviation Services Ltd | Transport & logistics | 2021 |
| Pear Media Ltd | Professional & scientific | 2004 |
| Peazy Ltd | Information & communication | 2020 |
| Pegasus Coatings Limited | Construction | 2024 |
| Penarth Travel Limited | Administrative & support | 2021 |
| Pencilgrass Holdings Ltd | Financial services | 2023 |
| Pencilgrass LLP | | 2023 |
| Penlan Properties Limited | Real estate | 2019 |
| Penllyn Estate Farm Limited | Agriculture & fishing | 2026 |
| Penllyn Estate LLP | | 2018 |
| Peterson-Super-Ely Development Ltd | Construction | 2025 |
| PH71 Hair Crew Limited | Other services | 2005 |
| Philip Jenkins Car Sales Limited | Real estate | 1982 |
| Photext Imaging Systems Limited | Administrative & support | 2006 |
| Physio Therapies Inspire Limited | Health & social care | 2015 |
| Piccadilly Beck Ltd | Professional & scientific | 2013 |
| Pink Flamingo Properties Limited | Real estate | 2018 |
| Pink Penguin Limited | Professional & scientific | 2020 |
| Pivos Ltd | Information & communication | 2026 |
| Pivox Ltd | Administrative & support | 2014 |
| Pixology Media Ltd | Extraterritorial | 2010 |
| Pixology Outdoor Ltd | Professional & scientific | 2010 |
| Place for Homes Limited(The) | Wholesale & retail | 1985 |
| PLB Ecowood South Limited | Agriculture & fishing | 2022 |
| Pleasant Dental Centre Ltd | Health & social care | 2022 |
| Plwca Developments Limited | Construction | 2007 |
| Plymdab Ltd | Information & communication | 2022 |
| PM Properties 1 Ltd | Construction | 2026 |
| PMM Property Management Limited | Real estate | 2023 |
| Pobol CYF | Professional & scientific | 2011 |
| Pole Position (Wales) Limited | Real estate | 2001 |
| Pontypridd Roofing Limited | Construction | 1995 |
| Porthcawl Buckaneers Limited | Arts & recreation | 2011 |
| Porthcawl Travel Limited | Administrative & support | 2022 |
| Powderbox Limited | Extraterritorial | 2010 |
| Powerfreight Limited | Administrative & support | 2009 |
| PPL Caron Ltd | Transport & logistics | 2003 |
| Praesidio Safeguarding Limited | Education | 2018 |
| Precisionfxpro Ltd | Other services | 2023 |
| Price Bros Properties Ltd | Real estate | 2018 |
| Prime Light Ltd | Information & communication | 2024 |
| Prime Properties 717 Ltd | Real estate | 2026 |
| Primrose Developments Ltd | Construction | 2019 |
| Principality Recycling Ltd | Water & waste | 2025 |
| Principality Skips Ltd | Water & waste | 2025 |
| Procex Solutions Ltd | Professional & scientific | 2012 |
| Proclean Services Group Limited | Administrative & support | 2026 |
| Project Martial Arts Ltd | Education | 2026 |
| Prossers Productions Ltd | Arts & recreation | 2022 |
| PRS70 Management Company Limited | Households | 2021 |
| PUM Blaen Properties Limited | Real estate | 2026 |