| O'R Pedwar Gwynt CYF. | Information & communication | 2016 |
| Ocean View Holidays Limited | Extraterritorial | 2003 |
| Octopws Innovation Limited | Professional & scientific | 2020 |
| Okay Car Valeting Ltd | Wholesale & retail | 2026 |
| Old Stables, Tanybwlch, Residents Association Limited(The) | Real estate | 1982 |
| ON the Road (Aberystwyth) Limited | Wholesale & retail | 2013 |
| Oscar Barber Ltd | Other services | 2026 |
| Osprey Service Management Limited | Information & communication | 2025 |
| OTB Labs Limited | Information & communication | 2026 |
| Ow's Cabs Aberystwyth Ltd | Transport & logistics | 2018 |
| Owen Evans Construction Ltd | Construction | 2025 |
| Owen Evans Developments Limited | Real estate | 2024 |
| P.D. Diners Limited | Hospitality | 2006 |
| P.P. Leisure Activities Limited | Arts & recreation | 1975 |
| P.P.M UK Construction Consultant Ltd | Construction | 2019 |
| P.T. Preservation Limited | Administrative & support | 2013 |
| Padarn Alarms Ltd | Construction | 2015 |
| Padarn Property Ltd | Real estate | 2021 |
| Padarn Systems Ltd | Construction | 2024 |
| Panthwylog Farm Ltd | Hospitality | 2020 |
| Parc Y Bryn Management Limited | Administrative & support | 2004 |
| Pato Properties Ltd | Real estate | 2020 |
| Paul Hill Ltd | Wholesale & retail | 2023 |
| Paul Ricketts Transport Ltd | Transport & logistics | 2016 |
| PEAK2PEAK Search Ltd | Administrative & support | 2022 |
| Pearly Bites Ltd | Manufacturing | 2021 |
| PEG and Geoff Ltd | Wholesale & retail | 2017 |
| Penbryn Properties Limited | Real estate | 2004 |
| Pendare Limited | Hospitality | 2024 |
| Penguine Joon Limited | Hospitality | 2024 |
| Penlanlas Cottages Limited | Hospitality | 2025 |
| Pennaeth CYF | Information & communication | 2025 |
| Pennau Ltd | Wholesale & retail | 2026 |
| Penny Pizza Limited | Hospitality | 2025 |
| Pennymortgages Limited | Financial services | 2015 |
| Penparcau Community Forum Ltd | Information & communication | 2014 |
| Penrhyn Stores Ltd | Wholesale & retail | 2008 |
| Penrhyn-Coch Investments Ltd | Construction | 2017 |
| Pentre Bach NI Cyfyngedig | Hospitality | 2003 |
| Penywern Properties Ltd | Real estate | 2025 |
| Pet Photography Ltd | Professional & scientific | 2023 |
| Phoenix Construction (DG) Limited | Construction | 2025 |
| Phytoquest Limited | Professional & scientific | 2009 |
| Picowatt Limited | Information & communication | 2026 |
| Pier Hotel 33 Limited | Hospitality | 2016 |
| Pihe Limited | Wholesale & retail | 2021 |
| Pili-Pala Collection Ltd | Wholesale & retail | 2009 |
| Pink Succulent Ltd | Professional & scientific | 2024 |
| Pizza Rulars Ltd | Hospitality | 2025 |
| Pizza Time Ltd | Hospitality | 2025 |
| Pizzalush.Com Limited | Hospitality | 2019 |
| PJ Farming Ltd | Agriculture & fishing | 2024 |
| Plas Cwmcynfelin Holding Company Limited | Financial services | 2024 |
| Plas Cwmcynfelin Investment Company Limited | Real estate | 2024 |
| Plas Cwmcynfelin Limited | Health & social care | 2004 |
| Plas Danycoed Management Company Limited | Households | 1964 |
| Plas Hafan Management Company Limited | Households | 2009 |
| Plas Mair Residents Association Limited | Other services | 1994 |
| Plas Morolwg Management Company Limited | Households | 2020 |
| Plas Nanteos Limited | Hospitality | 1998 |
| Plas Tanybwlch Management Company Limited | Households | 2021 |
| Plas YR Afon Residents Association Limited | Households | 1990 |
| Plasgrange Capital Partners | Financial services | 2021 |
| Platt Enterprises Ltd | Financial services | 2020 |
| Platts Huneez Ltd | Agriculture & fishing | 2020 |
| Plumbtech GAS & Heating Ltd | Construction | 2024 |
| PMD (Aberystwyth) Limited | Administrative & support | 2016 |
| Powell Davies Solicitors Limited | Professional & scientific | 2004 |
| PR Products Ltd | Wholesale & retail | 2025 |
| Probert & Williams EYE Care CYF | Wholesale & retail | 2018 |
| Prohempotic Ltd | Wholesale & retail | 2022 |
| Property Investment (Wales) Limited | Wholesale & retail | 1984 |
| Provecho Ltd | Hospitality | 2023 |
| Providence Essential Solutions Ltd | Wholesale & retail | 2026 |
| Prys Edwards Consultancy Limited | Real estate | 1989 |
| Puca Ltd. | Manufacturing | 2011 |
| Pugh Computers Limited | Wholesale & retail | 1991 |
| Pure Leisure Limited | Professional & scientific | 2022 |
| Pure Properties Group Limited | Real estate | 2019 |
| Pure Training Limited | Education | 2022 |
| Quality Welsh Food Certification Limited | Agriculture & fishing | 2000 |
| Quick Fence Hire Ltd | Construction | 2011 |
| R Haywood Plumbing & Heating Limited | Construction | 2010 |
| R Hopkins Construction Ltd | Construction | 2021 |
| R Taylor Music Ltd | Arts & recreation | 2026 |
| R.B. Jones Environmental Limited | Construction | 2016 |
| R.B. Jones Rentals Limited | Real estate | 2026 |
| Radical Value Alliance Limited | Health & social care | 2025 |
| Random Software Ltd | Information & communication | 2018 |
| Rapidboxsolutions Limited | Transport & logistics | 2025 |
| RAW Treat Pet Food Ltd | Manufacturing | 2018 |
| Rbrlettings Ltd | Real estate | 2025 |
| RD & GG Edwards Limited | Wholesale & retail | 2015 |
| RDS Events Wales Ltd | Arts & recreation | 2025 |
| Red Dart Ltd | Professional & scientific | 2018 |
| Redesigns-Uk Ltd | Manufacturing | 2022 |
| Rees Astley Credit Limited | Financial services | 1965 |
| Rees-Evans Limited | Construction | 2021 |
| Rehmani Limited | Health & social care | 2024 |
| Resonate Event Productions Wales Limited | Arts & recreation | 2023 |