| Piper Cycles Ltd | Other services | 2013 |
| Piper Smith Watton LLP | | 2007 |
| Pipestockist Limited | Extraterritorial | 2013 |
| Pirx Ltd | Information & communication | 2017 |
| Pishi Ltd | Professional & scientific | 2024 |
| Pivot Outdoors Ltd | Construction | 2025 |
| Pixelcraftbymonica Ltd | Wholesale & retail | 2025 |
| Pixelfunk.Io Ltd | Information & communication | 2024 |
| Pizza-Kins LLP | | 2025 |
| PJ Auto Hampshire Ltd | Wholesale & retail | 2013 |
| PJ Lambert Carpentry and Joinery Limited | Construction | 2012 |
| Pj's Valeting Ltd | Wholesale & retail | 2023 |
| PJC Tourism Services Limited | Administrative & support | 2015 |
| PJD Carpentry and Building Limited | Manufacturing | 2025 |
| PJD Leisure Management Ltd | Administrative & support | 2014 |
| PJM Rail Systems Ltd | Wholesale & retail | 2025 |
| PJO Cars Ltd | Wholesale & retail | 2018 |
| PJT Contracts Ltd | Construction | 2017 |
| PJT Logistics Limited | Transport & logistics | 2009 |
| Pkaf Investments Ltd. | Financial services | 1975 |
| PL London Ltd | Administrative & support | 2019 |
| Plan to Scale Ltd | Information & communication | 2026 |
| Plane Talking Products Ltd | Wholesale & retail | 2008 |
| Planet King Ltd | Information & communication | 2011 |
| Planet ME Ltd | Education | 2018 |
| Plannify Ltd | Construction | 2024 |
| Planning Recruitment Limited | Administrative & support | 2014 |
| Plantaholics Ltd | Wholesale & retail | 2022 |
| Plastic Mouldings Direct Ltd | Extraterritorial | 2011 |
| Plastica Alfa UK Limited | Professional & scientific | 2004 |
| Platform School of Dance Limited | Education | 2006 |
| Playground Football Ltd | Arts & recreation | 2024 |
| Plexico Limited | Manufacturing | 2018 |
| PLT Criminal Justice Consultancy Limited | Administrative & support | 2016 |
| Pltx Properties Limited | Real estate | 2023 |
| Plumb Medical Limited | Health & social care | 2020 |
| PM Music Ltd | Hospitality | 2022 |
| PM Plan Ltd | Professional & scientific | 2006 |
| PM Security Solutions Ltd | Administrative & support | 2017 |
| Pmsl Carpentry Limited | Construction | 2008 |
| PNB Property Services Ltd | Real estate | 2025 |
| Pncb Investments Limited | Real estate | 2019 |
| Pncb Southampton Ltd | Real estate | 2019 |
| Pncb Southampton Student Lettings Ltd | Real estate | 2019 |
| Pncb Winchester Ltd | Real estate | 2019 |
| Pncb Winchester Student Lettings Ltd | Real estate | 2019 |
| Pogtir Limited | Professional & scientific | 2024 |
| Pole Performers Dance School Ltd | Arts & recreation | 2010 |
| Polish Cleaning Team Ltd | Administrative & support | 2022 |
| Polish Retailer Ltd | Wholesale & retail | 2017 |
| Polka DOT Data Ltd | Information & communication | 2016 |
| POLY3D Ltd | Professional & scientific | 2024 |
| Polygon Col-Mar Limited | Real estate | 1999 |
| Pond Holdings Ltd | Financial services | 2015 |
| Poolbeg Ltd | Administrative & support | 2017 |
| Pople Holdings Limited | Financial services | 2025 |
| Pople Roofing Limited | Construction | 2006 |
| Poppie Consultancy Ltd | Professional & scientific | 1984 |
| Port Direct Logistics (Southampton) Limited | Transport & logistics | 2023 |
| Porterbrook Consulting Limited | Professional & scientific | 2025 |
| Porthleven Metalwork Limited | Manufacturing | 2005 |
| Portlands Construction Limited | Construction | 2024 |
| Portlands Property Management Limited | Real estate | 2024 |
| Portlands Property Services Limited | Construction | 2024 |
| Portsmouth Electricians 4U Limited | Construction | 2018 |
| Portswood Cars & Commercials Ltd | Wholesale & retail | 2019 |
| Portswood Computer Centre Ltd | Other services | 2013 |
| Posbrook Plant Services Ltd | Administrative & support | 2017 |
| Posh Babies Ltd | Wholesale & retail | 2022 |
| Posh Poos Ltd | Agriculture & fishing | 2019 |
| Posh Standards Ltd | Administrative & support | 2019 |
| Positive Vibes Limited Liability Partnership | | 2001 |
| Potaland Limited | Hospitality | 2026 |
| Pottiwal Lettings Ltd | Real estate | 2023 |
| Pouncing Panthers Limited | Health & social care | 2022 |
| Powells Electrical Services Limited | Extraterritorial | 2000 |
| Powells Group Limited | Financial services | 2002 |
| Powells Joinery Limited | Construction | 2000 |
| Powells Limited | Construction | 1985 |
| Power & Lighting Limited | Construction | 2006 |
| Power Forward Properties Ltd | Real estate | 2025 |
| Power Pricing Limited | Information & communication | 2025 |
| Power UP Limited | Construction | 2014 |
| Powered UP Electrical Limited | Construction | 2022 |
| Powerhouse Coaching Services Ltd | Arts & recreation | 2026 |
| Powerhouse Films Limited | Information & communication | 2016 |
| Powerhouse Films US Limited | Information & communication | 2020 |
| Powerhouse Supplements Ltd | Wholesale & retail | 2026 |
| Poyraz Limited | Hospitality | 2024 |
| PP Chinese Restaurant Limited | Hospitality | 2013 |
| PP Incentives Ltd | Wholesale & retail | 2021 |
| Ppfv Ltd | Wholesale & retail | 2022 |
| PQ Plumbers Ltd | Construction | 2014 |
| PR Shivam Limited | Professional & scientific | 2024 |
| Practice Resilience Ltd | Wholesale & retail | 2023 |
| Praeclarus Consulting Limited | Real estate | 2016 |
| Praeclarus Design Ltd | Professional & scientific | 2024 |
| Praedonum Limited | Education | 2018 |
| Praemurcia Limited | Mining & quarrying | 2022 |
| Prajos Medic Ltd | Professional & scientific | 2008 |