| Patagym Oy | Arts & recreation | 2022 |
| Patajunnuareena Oy | Real estate | 2007 |
| Paten Rengas Oy | Wholesale & retail | 2007 |
| Patripex Oy | Wholesale & retail | 1995 |
| Pavar Oy | Real estate | 2021 |
| PeSaNi Oy | Hospitality | 2015 |
| Peehoo 7 Ky | Water & waste | 2018 |
| Peittoon Kierrätysterminaali Oy | Wholesale & retail | 2014 |
| Pekatex Ky | Manufacturing | 1982 |
| Peki Kiinteistö Oy | Real estate | 2001 |
| Pekka Rae Ky | Construction | 1997 |
| Pekka ja Paula Koski Oy | Financial services | 1991 |
| Pelisilmä Oy | Education | 2026 |
| Pellonpään Puutarha Oy | Construction | 2014 |
| Pelti- ja ilmastointi Tuomola Oy | Construction | 1999 |
| Pelti-Pori Oy | Construction | 2012 |
| Peltisel Oy | Construction | 2019 |
| Pemalan Oy | Wholesale & retail | 2006 |
| Pendiente Oy | Hospitality | 1992 |
| Penkkimäki Oy | Construction | 1986 |
| Pentti Nurmi Oy | Wholesale & retail | 1993 |
| Penttiläntien jätevesiosuuskunta | Water & waste | 2019 |
| Peranta Oy | Administrative & support | 2003 |
| Perhekeskus Via Oy | Health & social care | 2022 |
| Perheravintola Happy Lunch Oy | Hospitality | 1993 |
| Perito Group Oy | Other services | 2017 |
| Pesu-Jumbo Ky | Wholesale & retail | 1981 |
| Pesupori Oy | Other services | 2012 |
| Petras Cafe Oy | Hospitality | 2023 |
| Petri Harju Oy | Professional & scientific | 2014 |
| Petri Torniainen Oy | Financial services | 2010 |
| PiSon Art Oy | Manufacturing | 2006 |
| PickMe Solutions Oy | Information & communication | 2026 |
| Pieni Olutpuoti Humala, Bar & Shop Oy | Hospitality | 2021 |
| Pieni ja pippurinen Oy | Hospitality | 1992 |
| Piesa Oy | Health & social care | 2023 |
| Pietikäinen ja Pietikäinen | Professional & scientific | 2003 |
| Pietilä ja Pojat Oy | Construction | 2016 |
| Pihakimmo Oy | Construction | 2014 |
| Pihlajamaan Musiikki Oy | Wholesale & retail | 2004 |
| Pihlavan Autohuolto Avoin Yhtiö | Other services | 1992 |
| Pihlavan Baari Avoin Yhtiö | Hospitality | 1992 |
| Piimäpirtin hautauspalvelu Oy | Other services | 2016 |
| Piitti Oy | Wholesale & retail | 2023 |
| Pikahuolto J Peltonen Oy | Other services | 2007 |
| Pikkuinen Paja2 Ky | Other services | 2013 |
| Pilates Tampere Oy | Education | 2024 |
| Pilpe Oy | Construction | 2021 |
| Pinnacle Smash OY | Hospitality | 2025 |
| Pinomäen Jätevesiosuuskunta | Water & waste | 2007 |
| Pinta Kipa Ky | Construction | 2005 |
| Pintatyö Koskela Oy | Construction | 2026 |
| Piparitalo Oy | Wholesale & retail | 2008 |
| Pir-Jus Oy | Construction | 1996 |
| Pirfa Oy | Other services | 2023 |
| Piritta Mäkinen Oy | Manufacturing | 2017 |
| Pirmaka Oy | Hospitality | 2019 |
| Pis Invest Oy | Real estate | 1990 |
| Pitopaakarit Ansa ja Lempi Avoin yhtiö | Wholesale & retail | 2002 |
| Pitopalvelu Amor Oy | Hospitality | 2026 |
| Pizzeria-Kahvila Rita's Place Oy | Hospitality | 1996 |
| PlanCore Oy | Professional & scientific | 2026 |
| Plastipap Oy | Wholesale & retail | 1992 |
| Playmaker Oy | Professional & scientific | 2007 |
| Plompuuki Oy | Financial services | 2023 |
| Plus Katsastus Pori Oy | Professional & scientific | 2010 |
| Podagra Oy | Health & social care | 2021 |
| Pohjakarin venepaikkaosuuskunta | Real estate | 1997 |
| Pohjolan Laatusaneeraus Oy | Construction | 2017 |
| Pohjolan Putkiremontit Oy | Construction | 2016 |
| Polar-Kylmä Oy | Manufacturing | 1979 |
| Polate Ky | Real estate | 1984 |
| Pollution Control Systems Finland Oy | Professional & scientific | 2007 |
| Pomarkun Hakeosuuskunta | Energy | 1998 |
| Pomatra Oy | Financial services | 1993 |
| Poosis Oy | Transport & logistics | 2015 |
| PopUppari Oy | Wholesale & retail | 2020 |
| Pori Energia Oy | Energy | 1990 |
| Pori Energia Sähköverkot Oy | Energy | 2006 |
| Pori Group Oy | Other services | 2015 |
| Pori Jazz Festival Oy | Arts & recreation | 2024 |
| Pori Kebab Pizzeria avoin yhtiö | Hospitality | 2019 |
| Pori Language Consulting Ky | Education | 1986 |
| PoriMaster Oy | Real estate | 2020 |
| Poricon Oy | Professional & scientific | 2003 |
| Porin AJ Rakennus Oy | Construction | 2015 |
| Porin Akvaariokeskus Oy | Wholesale & retail | 2009 |
| Porin Antennihuolto Oy | Construction | 2018 |
| Porin Antin-talot Oy | Real estate | 1996 |
| Porin Audiohuolto Ky | Other services | 2005 |
| Porin Auraaria Oy | Financial services | 2001 |
| Porin Auto Vene ja Romu Oy | Wholesale & retail | 2022 |
| Porin Auto ja Metalli Ky | Other services | 1990 |
| Porin Auto-Center Oy | Wholesale & retail | 2017 |
| Porin Auto-Sale Oy | Wholesale & retail | 1981 |
| Porin Autohuolto Oy | Other services | 2020 |
| Porin Automesta Oy | Wholesale & retail | 2013 |
| Porin Autopesu Oy | Other services | 2008 |
| Porin Autopiste Oy | Wholesale & retail | 2020 |
| Porin Autovälitys Oy | Wholesale & retail | 2023 |