| Porin Bitumikate Oy | Construction | 2017 |
| Porin City-Siivous ja Kiinteistönhuolto Oy | Administrative & support | 2017 |
| Porin EK-Putki ja kaasuasennus Ky | Manufacturing | 2012 |
| Porin Efox Oy | Wholesale & retail | 1992 |
| Porin Eko-Rakennus Oy | Construction | 1994 |
| Porin Elementtitehdas Oy | Manufacturing | 2022 |
| Porin Eläinlääkäripalvelu Oy | Professional & scientific | 2006 |
| Porin Erityiskiinteistöt Oy | Real estate | 2006 |
| Porin Eteläranta Oy | Hospitality | 2019 |
| Porin Faster Ky | Construction | 1995 |
| Porin Haka Oy | Real estate | 2011 |
| Porin Hallijäähdyttämö Ky | Real estate | 1989 |
| Porin Hallinrakentajat Oy | Real estate | 2013 |
| Porin Hammaspalvelu Oy | Health & social care | 2023 |
| Porin Heidi Nurmi Oy | Hospitality | 2012 |
| Porin Hifi store Oy | Wholesale & retail | 2007 |
| Porin Hitsauslaite Oy | Wholesale & retail | 2008 |
| Porin Hius- ja Kauneusklinikka Oy | Other services | 2011 |
| Porin Honka-kiinteistöt Oy | Real estate | 1996 |
| Porin Huoltocenter Oy | Other services | 2005 |
| Porin Huoltohalli Oy | Real estate | 1978 |
| Porin Huoltokeskus Ky | Other services | 1987 |
| Porin Huoltoteam Oy | Manufacturing | 2023 |
| Porin Hydrotekniikka Oy | Wholesale & retail | 2014 |
| Porin Hyötyajoneuvot Oy | Wholesale & retail | 1993 |
| Porin IV-Huolto Oy | Construction | 2021 |
| Porin Invataksi Oy | Transport & logistics | 1986 |
| Porin Isännöintipalvelut Oy | Real estate | 1993 |
| Porin Itäkeskuksen Kultakoru Oy | Wholesale & retail | 2002 |
| Porin JPL-Asunnot Oy | Construction | 2014 |
| Porin Jalopuuparketti Oy | Construction | 1992 |
| Porin Juhlava Oy | Administrative & support | 1993 |
| Porin Juoksupoika Oy | Administrative & support | 2013 |
| Porin Kala M. Riuttala Ky | Wholesale & retail | 1983 |
| Porin Kalliokiinteistöt Oy | Real estate | 2017 |
| Porin Kaluste-Etappi Ky | Manufacturing | 1991 |
| Porin Kamppailu-urheilukeskus Oy | Arts & recreation | 2011 |
| Porin Kespa Kiinteistöt Oy | Real estate | 1999 |
| Porin Kespa Oy | Financial services | 1985 |
| Porin Kiinteistöpiste Oy | Real estate | 1989 |
| Porin Kiitomies Oy | Transport & logistics | 1997 |
| Porin Kirjakauppa Oy | Wholesale & retail | 2006 |
| Porin Kirjanpito Oy | Professional & scientific | 1993 |
| Porin Kirvestyö Ky | Construction | 1983 |
| Porin Kivitalot Ky | Construction | 1999 |
| Porin Kodinrakennus Oy | Construction | 1994 |
| Porin Kone-Tuonti Oy | Wholesale & retail | 2001 |
| Porin Koneautomaatio Oy | Manufacturing | 1990 |
| Porin Konecenter Oy | Wholesale & retail | 2023 |
| Porin Konera Oy | Wholesale & retail | 1961 |
| Porin Konevuokraus Oy | Real estate | 1977 |
| Porin Konttorihuolto Oy | Manufacturing | 1974 |
| Porin Konttorikone Oy | Wholesale & retail | 1974 |
| Porin Konttuuri Ky | Real estate | 2002 |
| Porin Koru Oy | Wholesale & retail | 2019 |
| Porin Kotini LKV Oy | Real estate | 2022 |
| Porin Kotipalvelu Oy | Construction | 2013 |
| Porin Kuljetus tiimi Oy | Transport & logistics | 1995 |
| Porin Kultaprisma Ky | Wholesale & retail | 1990 |
| Porin Kulttuuriresidenssi Oy | Arts & recreation | 1989 |
| Porin Kunnon Fiilis Oy | Arts & recreation | 1998 |
| Porin Kuntohalli Oy | Arts & recreation | 1989 |
| Porin Kuntokeskus Oy | Arts & recreation | 1999 |
| Porin Kuntotorni Oy | Arts & recreation | 2006 |
| Porin Kylmäasennus Oy | Construction | 1987 |
| Porin Kylmäkone Grönbacka Ky | Manufacturing | 1976 |
| Porin Kylmälaite Olli Oksa Ky | Construction | 1985 |
| Porin Kylmävuokraus Oy | Administrative & support | 2023 |
| Porin Laatuleipä, Kommandiittiyhtiö Laihinen | Manufacturing | 1964 |
| Porin Laatupaino Oy | Manufacturing | 2025 |
| Porin Laatuputki Group Oy | Construction | 2021 |
| Porin Laaturakennus Oy | Real estate | 1990 |
| Porin Laatutalo Oy | Construction | 1990 |
| Porin Laatuteräs Oy | Manufacturing | 1987 |
| Porin Laatuvalu Ky | Manufacturing | 1988 |
| Porin Laatuvaraosa Oy | Wholesale & retail | 1979 |
| Porin Laitetilarakentajat Oy | Construction | 2015 |
| Porin Laiva & Satamapalvelu Oy | Real estate | 1995 |
| Porin Lattiamiehet Oy | Construction | 2023 |
| Porin Lautamiehet Oy | Wholesale & retail | 1995 |
| Porin Leipä Oy | Manufacturing | 1978 |
| Porin Lentotilaus Oy | Transport & logistics | 1995 |
| Porin Levy ja Hitsaus Oy | Manufacturing | 1955 |
| Porin Levykauppa Oy | Wholesale & retail | 2016 |
| Porin Linjat Oy | Transport & logistics | 1934 |
| Porin Linjuriauto Oy | Transport & logistics | 2014 |
| Porin Lukko Oy | Wholesale & retail | 1976 |
| Porin Luontaistuote ja Homeopatia Oy | Wholesale & retail | 1998 |
| Porin Länsituote Oy | Manufacturing | 1990 |
| Porin Maalaustyöt Oy | Construction | 1971 |
| Porin Maastotyö Oy | Construction | 1994 |
| Porin Mattotyö Oy | Construction | 1987 |
| Porin Melvis Oy | Real estate | 1997 |
| Porin Mestaripizzat Oy | Hospitality | 1995 |
| Porin Miittinki Ky | Hospitality | 1997 |
| Porin Mikkolantie 15 Oy | Financial services | 1987 |
| Porin Monipalvelu Oy | Real estate | 2020 |
| Porin Muotti ja Puristus Oy | Manufacturing | 2016 |
| Porin Murre Oy | Wholesale & retail | 2019 |
| Porin Musiikki Ky | Wholesale & retail | 1986 |