| Peterborough United Football Club Limited | Arts & recreation | 1934 |
| Peterborough United Foundation | Arts & recreation | 2009 |
| Peterborough Value Store Ltd | Wholesale & retail | 2026 |
| Peterborough Wakepark Limited | Arts & recreation | 2015 |
| Peterborough Weight Training Club Limited | Arts & recreation | 2001 |
| Peterborough Windows and Conservatories Ltd | Construction | 2021 |
| Peterborough Windscreens Limited | Other services | 2017 |
| Peterborough's Active Youth (P.A.Y) Community Interest Company | Education | 2026 |
| Peterboroughflooring Ltd | Wholesale & retail | 2019 |
| Peterboroughgrabuk Limited | Transport & logistics | 2024 |
| Peterboroughnlp Limited | Professional & scientific | 2015 |
| Peterboroughvillage Stores Limited | Wholesale & retail | 2024 |
| Peters Traditional Bakery Ltd | Manufacturing | 2025 |
| Petersfield (Kings Road) Residents Company Limited | Households | 2013 |
| Petiole Ltd | Agriculture & fishing | 2017 |
| Petm Ltd | Transport & logistics | 2021 |
| Petmar Limited | Transport & logistics | 2023 |
| Petre Szasz Engineering Ltd | Construction | 2019 |
| Petro OIL Ltd | Construction | 2025 |
| Pets Fluffy Paws Ltd | Administrative & support | 2026 |
| Pets Love Fresh Limited | Manufacturing | 2014 |
| Pettitt Joinery Company Limited | Administrative & support | 1974 |
| Pettitt Joinery Holdings Limited | Professional & scientific | 2009 |
| Peugeot Pizza Truck Co Ltd | Hospitality | 2025 |
| Pexpex Ltd | Wholesale & retail | 2022 |
| Pezula Property Limited | Hospitality | 2025 |
| PF & C Ltd | Hospitality | 2019 |
| PF & MF Limited | Professional & scientific | 2024 |
| PF Car Service Ltd | Wholesale & retail | 2016 |
| PF Firesoft Ltd | Professional & scientific | 2015 |
| PG Farms Ltd | Agriculture & fishing | 2018 |
| PG Treasury Limited | Professional & scientific | 2011 |
| PG1 Investment Ltd | Information & communication | 2023 |
| PGK Developments Limited | Real estate | 2021 |
| PGM Mortgage Services Limited | Financial services | 2018 |
| PGP Products (UK) Ltd | Wholesale & retail | 2020 |
| PGR Group Limited | Construction | 2009 |
| PGR Healthcare Ltd | Wholesale & retail | 2024 |
| Pgrg 1 Ltd | Real estate | 2024 |
| Pgro Research Limited | Professional & scientific | 2011 |
| PGS Rentals Limited | Real estate | 2021 |
| PH Welland Ltd | Real estate | 2026 |
| Phantom Screens (UK) Limited | Manufacturing | 2006 |
| Pharez Consult Ltd | Health & social care | 2015 |
| Pharma Base NV Ltd | Administrative & support | 2025 |
| Pharma Indepth Ltd | Professional & scientific | 2025 |
| Pharma Practitioners Ltd | Health & social care | 2022 |
| Pharmacetamol Ltd | Professional & scientific | 2021 |
| Pharmacourier Ltd | Transport & logistics | 2024 |
| Pharmacy Medicines Ltd | Manufacturing | 2011 |
| Pharmacy Meds Ltd | Wholesale & retail | 2022 |
| Pharmanisa Ltd | Health & social care | 2023 |
| Pharmaworld Ltd | Wholesale & retail | 2022 |
| Phase 10 Apartments 306-333 Buttercross Mews Management Company Limited | Households | 2022 |
| Phase 9 Apartments 143-157 Farriers Mews (Oakham) Management Company Limited | Households | 2022 |
| Phat'Z Kitchen Ltd | Hospitality | 2025 |
| Phaze Recruitment Ltd | Administrative & support | 2021 |
| PHB Services Ltd | Construction | 2025 |
| PHC Supplies Limited | Wholesale & retail | 2020 |
| PHI Architectural Design (PAD) Limited | Professional & scientific | 2018 |
| Phil West Limited | Information & communication | 2015 |
| Philip Houlden Court Management Company Limited | Households | 2006 |
| Philip Lees Write Words Limited | Professional & scientific | 2016 |
| Phillips 121 Ltd | Professional & scientific | 2020 |
| Philtinz Ltd | Construction | 2025 |
| Phoebus Tutors Limited | Education | 2025 |
| Phoenix Architectural Ironmongery Limited | Extraterritorial | 1993 |
| Phoenix Driving School Ltd | Education | 2018 |
| Phoenix Field Medical Ltd | Professional & scientific | 2026 |
| Phoenix Firewalk Limited | Other services | 2007 |
| Phoenix Global Services (UK) Limited | Wholesale & retail | 2013 |
| Phoenix Golf Ltd | Manufacturing | 2024 |
| Phoenix Gymnastics Centre Peterborough Limited | Arts & recreation | 2017 |
| Phoenix Properties Enterprise Ltd | Real estate | 2021 |
| Phoenix Rock Holdings Ltd | Financial services | 2022 |
| Phoenix Technical Emea Ltd | Professional & scientific | 2024 |
| Phoenix Vapers Limited | Wholesale & retail | 2018 |
| Phoenix Vapers Online Limited | Wholesale & retail | 2023 |
| Phoenix Youth Provision CIC | Other services | 2022 |
| Phone Trader Newark Ltd | Wholesale & retail | 2024 |
| Phone Walia Ltd | Wholesale & retail | 2019 |
| Phone-Plus Ltd | Wholesale & retail | 2005 |
| Phones (UK) Limited | Wholesale & retail | 2013 |
| Phonese UK Ltd | Wholesale & retail | 2020 |
| Phonexperts Ltd | Professional & scientific | 2015 |
| Photocentric Limited | Manufacturing | 2002 |
| Phychembiomat Solutions (2018) Ltd | Education | 2022 |
| Physeek Leisure Ltd | Arts & recreation | 2017 |
| Physio Rehab @ Home Ltd | Health & social care | 2023 |
| Physio Well Ltd | Health & social care | 2025 |
| PI Investors Ltd | Real estate | 2026 |
| Picday Ltd | Professional & scientific | 2020 |
| Pick ME UP Cars Ltd | Transport & logistics | 2024 |
| Pickett Produce Limited | Wholesale & retail | 2015 |
| Pickwell Plumbing & Heating Ltd | Construction | 2006 |
| Pics on Canvas Ltd | Manufacturing | 2018 |
| Picture Quality Prints Ltd | Professional & scientific | 2020 |
| Pigco Limited | Professional & scientific | 2025 |
| Pijmy Limited | Administrative & support | 2018 |
| Piksel Ltd | Wholesale & retail | 2025 |