| Oy Mäntyluoto Terminals Ltd. | Real estate | 1972 |
| Oy Oil Innovation Finland Ltd | Manufacturing | 2020 |
| Oy Orasel Ltd | Manufacturing | 2004 |
| Oy Porin Hanke Ab | Transport & logistics | 1997 |
| Oy Program-Production, Pori, Ltd | Professional & scientific | 1984 |
| Oy Rör & Svetsteam Ab | Construction | 1987 |
| Oy SNcargo Ltd | Transport & logistics | 1987 |
| Oy Satakunnan Vihanneskauppa Ab | Wholesale & retail | 2026 |
| Oy Scandic Niinivirta Ab | Transport & logistics | 2001 |
| Oy Skog Scandinavia Ab | Wholesale & retail | 2007 |
| Oy Succee Ab | Professional & scientific | 2007 |
| Oy Suomen Teknologiakeskus Ab | Professional & scientific | 1994 |
| Oy Transrunner Ltd | Transport & logistics | 1997 |
| Oy Transwik Ab | Professional & scientific | 1985 |
| Oy Vino Veritas Skandinavia Ltd. | Wholesale & retail | 2005 |
| Oy Wosret Ab | Other services | 2012 |
| Oy Zieff Ltd. | Professional & scientific | 1989 |
| P & T Riikoset OY | Professional & scientific | 2014 |
| P&G Food Oy | Hospitality | 2015 |
| P-R Talous ja Vuokraus Oy | Professional & scientific | 1979 |
| P. Lammi & Kumpp. | Manufacturing | 1983 |
| P.Kurkio Oy | Wholesale & retail | 1989 |
| P.Ramstedt Consulting Oy | Other services | 2021 |
| PC Production Oy | Manufacturing | 1993 |
| Pcbdroid OY | Information & communication | 2018 |
| PCY Oy | Arts & recreation | 2017 |
| Peto-Works OY | Manufacturing | 2009 |
| PH Support&Consulting Oy | Water & waste | 2023 |
| PJK Palvelut Oy | Information & communication | 2012 |
| PJT Kiinteistöt Oy | Real estate | 2017 |
| PJV-Process Team Oy | Manufacturing | 2001 |
| PK Controller Oy | Professional & scientific | 2005 |
| PK Entertainment Oy | Arts & recreation | 2026 |
| Pk-Laskenta OY | Professional & scientific | 1990 |
| Pk-Pakkaus OY | Manufacturing | 2015 |
| PK-Taberna Oy | Hospitality | 2014 |
| PKH Consulting Oy | Financial services | 2012 |
| PKT Property Oy | Financial services | 2026 |
| Plamag OY | Wholesale & retail | 2026 |
| PLS Powerline Service Oy | Construction | 2019 |
| PM Project Oy | Financial services | 2025 |
| Porez OY | Health & social care | 2008 |
| Porin Konehuolto OY | Other services | 2006 |
| Porin Konekeskus OY | Wholesale & retail | 2016 |
| Porin Maahantuonti OY | Wholesale & retail | 2016 |
| PORIN TAKKA Ky | Wholesale & retail | 2016 |
| Porin Transline Ky | Transport & logistics | 2007 |
| POSTART Oy | Arts & recreation | 2021 |
| PP Connect Oy | Construction | 1990 |
| PP Property Management Oy | Real estate | 2009 |
| PP-Yrityspalvelut Oy | Professional & scientific | 2016 |
| PRINZ v PREUSSEN GmbH Oy | Manufacturing | 2019 |
| PRK Kone Huolto OY | Other services | 2023 |
| PRM-Yhtiöt Oy | Construction | 1992 |
| Pro LV1 OY | Construction | 2018 |
| PS-Autohuolto Oy | Other services | 2017 |
| PS-Kortit Oy | Wholesale & retail | 2015 |
| PT Precision Technologies Oy | Manufacturing | 1994 |
| PTP Energia Oy | Administrative & support | 2012 |
| PTP Vuokraus Oy | Administrative & support | 2012 |
| PTP Yhtiöt Oy | Professional & scientific | 2021 |
| Paakari Jukka Ky | Manufacturing | 1984 |
| Paapuuri Oy | Agriculture & fishing | 1994 |
| Paaskari OY | Financial services | 1988 |
| Padel Imperium Oy | Arts & recreation | 2021 |
| Painepiste Oy | Wholesale & retail | 2010 |
| Paja-Jussit Oy | Real estate | 1987 |
| Paja23 Oy | Information & communication | 2020 |
| PalatsiGym Oy | Arts & recreation | 2017 |
| Palmiatek Oy | Manufacturing | 1985 |
| PaloRohto Oy | Wholesale & retail | 2024 |
| Paluksen kuivuri- ja koneosuuskunta | Administrative & support | 1957 |
| Palvelukari Oy | Administrative & support | 2022 |
| Palvelutukku Immonen Oy | Wholesale & retail | 1982 |
| Panacea BD-LK Oy | Hospitality | 2026 |
| Panelian Metallirakenne Oy | Manufacturing | 1989 |
| Panelian Rakennustarvike Ky | Wholesale & retail | 1976 |
| Panimoravintola Beer Hunter's Oy | Hospitality | 2009 |
| Panu Vihla Oy | Health & social care | 2023 |
| Papa-Center Oy | Health & social care | 1977 |
| Paprotec Oy | Professional & scientific | 2003 |
| Paratiisi Cafe Bar Oy | Hospitality | 2024 |
| Paremmax Oy | Education | 2009 |
| Pares Oy | Health & social care | 2005 |
| Paripori Oy | Real estate | 2026 |
| Parkeria Oy | Financial services | 1990 |
| Parketti- ja mattotyö J Koivisto Oy | Construction | 1993 |
| Partisan gym oy | Arts & recreation | 2020 |
| PartlySunny&Nice Oy Ab | Professional & scientific | 2025 |
| Parturi-Kampaamo Jasminella avoin yhtiö | Other services | 1984 |
| Parturi-Kampaamo Kirsi Virtanen Oy | Other services | 2013 |
| Parturi-Kampaamo Porin Kiehkura Oy | Other services | 1994 |
| Parturi-Kampaamo Sanna Tuulia Oy | Other services | 2020 |
| Parturi-Kampaamo Sävel Ky | Other services | 2009 |
| Pasi Tammi Oy | Arts & recreation | 2004 |
| Pasiq Oy | Professional & scientific | 2020 |
| Paspis Oy | Manufacturing | 1992 |
| Pastuskeri - Anttoora vesiosuuskunta | Water & waste | 1997 |
| Pastuskerin Ranta ja Tie Oy | Administrative & support | 2007 |
| Pata Production Oy | Administrative & support | 2011 |