| Peterscroft Construction Limited | Construction | 2013 |
| Petersfield Childcare Hub Ltd | Education | 1996 |
| Petev Ltd | Wholesale & retail | 2017 |
| Petite Playhouse Ltd | Wholesale & retail | 2025 |
| Petmarc Ltd | Transport & logistics | 2019 |
| Petpals (International) Limited | Professional & scientific | 2008 |
| Petre M Ltd Ltd | Transport & logistics | 2021 |
| Petro-Chem-Energy Services Ltd | Professional & scientific | 2016 |
| Petrona Property Limited | Construction | 2024 |
| Petrov Construction Limited | Construction | 2022 |
| Peveril Holdings Ltd | Other services | 2015 |
| Peviap Limited | Construction | 2014 |
| PEW Property (Rental) Limited | Real estate | 2003 |
| PEW Signalling Ltd | Construction | 2017 |
| PEW Studio Limited | Information & communication | 2008 |
| Pexigo Ltd | Wholesale & retail | 2025 |
| Peyto Logistics Ltd | Transport & logistics | 2025 |
| Pezco Ltd | Professional & scientific | 2025 |
| Pfeifer Rope and Tackle Limited | Manufacturing | 1980 |
| PFP Palace Coaching Limited | Education | 2025 |
| PFS Global Services UK Limited | Information & communication | 1998 |
| PG Compliant Ltd | Professional & scientific | 2024 |
| PG Court Limited | Households | 2018 |
| Pg-Sterling UK Limited | Financial services | 2018 |
| PGB Residential Ltd | Real estate | 2022 |
| PGD Properties Ltd | Real estate | 2024 |
| Pgeastwood Consulting Limited | Professional & scientific | 2025 |
| PGH Decorating Limited | Construction | 2010 |
| PGL Projects Ltd | Construction | 2021 |
| PGP IT Ltd | Information & communication | 2025 |
| Pgss Company Limited | Transport & logistics | 2012 |
| PH Survey Engineering Limited | Professional & scientific | 2015 |
| Phagura Properties Ltd | Households | 2023 |
| Phantom Limb Touring Limited | Arts & recreation | 2023 |
| Pharlap Property Ltd | Real estate | 2017 |
| PHARM24 Ltd | Wholesale & retail | 2013 |
| Pharmaland Ltd | Wholesale & retail | 2022 |
| Pharmalpha Limited | Health & social care | 2009 |
| Pharmangelist Limited | Health & social care | 2008 |
| Pharmarajel Ltd | Professional & scientific | 2024 |
| Pharmht Limited | Wholesale & retail | 2022 |
| Pharmlink Ltd | Health & social care | 2024 |
| Pharmloc Ltd | Wholesale & retail | 2021 |
| Pharmsouth Limited | Manufacturing | 2007 |
| Phase 3 Plastics Limited | Manufacturing | 1976 |
| Phase One Mechanical & Electrical Ltd | Manufacturing | 2025 |
| Phase Three Holdings Limited | Professional & scientific | 2022 |
| Phaymerphoto Ltd | Professional & scientific | 2024 |
| Phaze Electrics Ltd | Construction | 2025 |
| PHC Southampton Ltd | Construction | 2020 |
| Phelps Coilwinding Limited | Construction | 2013 |
| Phenix Heart Limited | Education | 2022 |
| Pheonix Eco Homes Ltd | Construction | 2026 |
| PHG Consultancy Limited | Administrative & support | 2011 |
| Phigz Limited | Administrative & support | 2023 |
| Phil Gallagher Consulting Ltd | Professional & scientific | 2022 |
| Phil Hughes Design Limited | Other services | 2016 |
| Phil Renn Ltd | Information & communication | 2004 |
| Phil Thomas Video Ltd | Information & communication | 2015 |
| Philip Gray Consultancy Services Ltd | Professional & scientific | 2020 |
| Phill Reeves Carpentry and Building Ltd | Construction | 2003 |
| Phillip Nuttall Kitchens Limited | Construction | 2008 |
| Phillips Birch Property Limited | Real estate | 2024 |
| Phillips Media Group Limited | Wholesale & retail | 2015 |
| Philspace Limited | Administrative & support | 1975 |
| PHM (Retail & Property) Solutions Ltd | Professional & scientific | 2017 |
| Phobia UK Ltd | Health & social care | 2023 |
| Phoenix ARB Group Ltd | Administrative & support | 2025 |
| Phoenix Asset Services Limited | Real estate | 2022 |
| Phoenix Facades Ltd | Construction | 2020 |
| Phoenix Fire Extinguisher Services Limited | Public administration | 2003 |
| Phoenix Freight Xpress Ltd | Transport & logistics | 2024 |
| Phoenix GC Holdings Ltd | Real estate | 2026 |
| Phoenix Independence Ltd | Health & social care | 2018 |
| Phoenix Independence Services Limited | Health & social care | 2022 |
| Phoenix Office Cleaning Limited | Administrative & support | 2008 |
| Phoenix Power Solutions Ltd | Professional & scientific | 2011 |
| Phoenix Project Solutions Ltd | Administrative & support | 2011 |
| Phoenix Property & Maintenance Ltd | Construction | 2025 |
| Phoenix Sibley Limited | Real estate | 2021 |
| Phoenix SMA Ltd | Arts & recreation | 2014 |
| Phone Gadgets 4 U Eastleigh Ltd | Wholesale & retail | 2026 |
| Phone Studio Hove Ltd | Wholesale & retail | 2025 |
| Phone Tech Vape Limited | Wholesale & retail | 2025 |
| Phoneboss Exeter Ltd | Manufacturing | 2020 |
| Phonecom Ltd | Information & communication | 2018 |
| Phonet Limited | Administrative & support | 2022 |
| Phonetech MUK Limited | Wholesale & retail | 2026 |
| Phonon Property Management Limited | Real estate | 2024 |
| Photo Solutions Studios Limited | Wholesale & retail | 2010 |
| Photogramia Limited | Extraterritorial | 2010 |
| Photored Ltd | Professional & scientific | 2013 |
| PHP Volt Limited | Information & communication | 2026 |
| PHX Southampton Limited | Arts & recreation | 2018 |
| Phydes Limited | Administrative & support | 2009 |
| Physics, Aviation and Data Science Research Ltd | Information & communication | 2017 |
| Physio Fast Ltd | Health & social care | 2025 |
| Physio Force Limited | Health & social care | 2007 |
| PIC Perfy Style Ltd | Wholesale & retail | 2023 |
| Picador Limited | Wholesale & retail | 1963 |