| Osborne Court Management Company Limited | Households | 1981 |
| Oscar and Patch Limited | Manufacturing | 2023 |
| Oscar Walter Parson Ltd | Extraterritorial | 2020 |
| Oscy AID Ltd | Health & social care | 2021 |
| OSD South West Group Ltd | Information & communication | 2019 |
| Osen Textile Technology Limited | Professional & scientific | 2007 |
| Oshen Ltd | Professional & scientific | 2022 |
| OSO Travel Ltd | Information & communication | 2021 |
| Osteo Marketing Ltd. | Professional & scientific | 2024 |
| Osterley Building Services Limited | Construction | 2010 |
| OTJ Ltd | Transport & logistics | 2016 |
| OTM Builders Ltd | Construction | 2022 |
| Otter Nurseries of Plymouth Limited | Wholesale & retail | 1996 |
| Ottowa Holding Ltd | Financial services | 2026 |
| Ottowa Limited | Construction | 2022 |
| OUR Earth Group Limited | Construction | 2023 |
| OUR Occupational Health Limited | Health & social care | 2026 |
| OUR People Ltd | Information & communication | 2013 |
| OUR Planet Photography Limited | Professional & scientific | 2017 |
| Outdoor and Countryside Brands Ltd | Manufacturing | 2019 |
| Outersight (UK) Limited | Construction | 2005 |
| Outfox Outdoors Ltd | Wholesale & retail | 2025 |
| Output Productions Limited | Information & communication | 2023 |
| Outside Dimension LLP | | 2019 |
| Outsourcery Services LLP | | 2022 |
| Over the Top Cornish Pasty Co. Ltd | Extraterritorial | 2017 |
| Overbridge Capital Ltd | Financial services | 2019 |
| Owen James Industrial Roofing and Cladding Limited | Construction | 2016 |
| OWL Services Ltd | Health & social care | 2024 |
| Oxinternet Limited | Professional & scientific | 2012 |
| Oxygen Centre Ltd | Health & social care | 2021 |
| Oyster House Ltd | Professional & scientific | 2014 |
| Ozon Garage Plymouth Ltd | Wholesale & retail | 2016 |
| Ozone Tech Limited | Administrative & support | 2014 |
| Ozzys Specialist Haulage Ltd | Transport & logistics | 2025 |
| P & a Services South West Limited | Administrative & support | 2009 |
| P & L Tool Solutions Ltd | Wholesale & retail | 2019 |
| P & S Hinchliffe Ltd | Professional & scientific | 2018 |
| P & X Bailey LLP | | 2016 |
| P C Properties (Plymouth) Limited | Real estate | 2023 |
| P Edwards Properties Limited | Real estate | 2020 |
| P F Industries Ltd | Construction | 2015 |
| P J Oliver (Cornwall) Limited | Other services | 2026 |
| P K Northmore Ltd | Financial services | 2016 |
| P Kamaie Property Limited | Real estate | 2016 |
| P L (Freeholds) Ltd | Real estate | 1994 |
| P L (Ground Rent) Ltd | Real estate | 1998 |
| P M C H Developments | Hospitality | 1996 |
| P O D Social Care Ltd | Health & social care | 2010 |
| P Royston Ltd | Education | 2019 |
| P&K Ashton Holdings Limited | Financial services | 2021 |
| P&R Power Systems Ltd | Professional & scientific | 2025 |
| P.A.K. Building Services South West Ltd | Construction | 2023 |
| P.G.Rogers Ltd | Agriculture & fishing | 2025 |
| P.K Paranormal Ltd | Administrative & support | 2025 |
| P.N. & M.P. Hamilton Limited | Agriculture & fishing | 1977 |
| P.Roots Properties Limited | Real estate | 2024 |
| P.T.G. Precision Engineers Limited | Professional & scientific | 1979 |
| P7 Kitchen Commercial Ltd | Construction | 2016 |
| PA 2018 Holdings Ltd | Financial services | 2024 |
| PA Properties Group Ltd | Real estate | 2025 |
| Packhelp Limited | Administrative & support | 2022 |
| Padel Tribe Limited | Arts & recreation | 2025 |
| Padre E Figlio Ltd | Hospitality | 2017 |
| Paella Pals Ltd | Hospitality | 2025 |
| Page Construction (SW) Limited | Construction | 2021 |
| Pagoda Drive Apartments Management Limited | Households | 2022 |
| Paintjar Finishes Ltd | Construction | 2025 |
| Paixray Limited | Wholesale & retail | 2026 |
| Pakaya Limited | Professional & scientific | 2021 |
| Palace Lodges Limited | Construction | 2022 |
| Palace Vaults (Freehold) Limited | Households | 2014 |
| Palladium Limited | Wholesale & retail | 1980 |
| Palm Domestic Services Limited | Professional & scientific | 2018 |
| Palmer Greenwood Limited | Professional & scientific | 2017 |
| Palmerplan Limited | Administrative & support | 2009 |
| Palms Land Ltd | Wholesale & retail | 2024 |
| Pancake Print Shop Ltd | Manufacturing | 2019 |
| Pandy Properties Limited | Real estate | 2019 |
| Panoptic Consultancy Group Ltd | Professional & scientific | 2020 |
| Panorama Associates Limited | Households | 1982 |
| Pansewn Studios Ltd | Manufacturing | 2026 |
| Pantaenius U.K. Limited | Financial services | 1990 |
| Pantheon Health & Fitness Ltd | Arts & recreation | 2019 |
| Papa Fletch Ltd | Hospitality | 2023 |
| Papag.Ai Ltd | Information & communication | 2025 |
| Paparaj Ltd | Hospitality | 2013 |
| Paper Records Ltd | Information & communication | 2019 |
| Papmoore Limited | Transport & logistics | 2018 |
| PAR Market Limited | Real estate | 2017 |
| Parachute Marketing Agency Limited | Professional & scientific | 2020 |
| Parade 2025 LLP | | 2025 |
| Paradigm Investment Group Limited | Professional & scientific | 2020 |
| Paragon Renewables UK Ltd | Energy | 2026 |
| Paramount Coaches Limited | Transport & logistics | 2003 |
| Parapet Property Ltd | Real estate | 2026 |
| Parcway Developments Limited | Construction | 2002 |
| Parcway House Tenants Management Company Limited | Real estate | 2007 |
| Park Garage Motor Ltd | Wholesale & retail | 2021 |
| Park Hall (Torquay) Limited | Households | 2001 |