| HealingVibe Oy | Manufacturing | 2025 |
| HeatPro Oy | Real estate | 2011 |
| HeavyWash Oy | Other services | 2019 |
| Hehku-Pro Oy | Wholesale & retail | 2023 |
| HeiSal Oy | Construction | 2008 |
| Heikki Hakoniemi Kommandiittiyhtiö | Hospitality | 1989 |
| Heikki Westerbacka Ky | Transport & logistics | 1988 |
| Heimari Oy | Professional & scientific | 1988 |
| Heinilä Invest Oy | Financial services | 2006 |
| Heinilä Sijoitus Oy | Financial services | 2015 |
| Heinonen Group Oy | Other services | 1982 |
| Heinox-Hormit Oy | Manufacturing | 1997 |
| Heistea Oy | Wholesale & retail | 2003 |
| Hejuka Oy | Real estate | 2021 |
| Helexia Oy, Porin Asuntovuokraus | Real estate | 1995 |
| Helmi Force Oy | Professional & scientific | 2017 |
| Helmi Venture Oy | Financial services | 2024 |
| HelpArea Oy | Education | 2022 |
| HepoVet Oy | Professional & scientific | 2020 |
| Herita Oy | Construction | 2008 |
| Herkkuvaara Oy | Hospitality | 2020 |
| Herralahden Huolto Oy | Administrative & support | 1966 |
| Herran Pelit Oy | Arts & recreation | 2021 |
| Herttua-Invest Oy | Real estate | 1996 |
| Hesa Invest Oy | Real estate | 2004 |
| Hesarest Kommandiittiyhtiö | Education | 1989 |
| Hetkone Oy | Manufacturing | 2024 |
| Heurtek Oy | Professional & scientific | 2024 |
| Heuwerk Oy | Professional & scientific | 2009 |
| Hevosellesi Oy | Wholesale & retail | 2018 |
| Hietalocale Oy | Real estate | 2026 |
| Hietalämpö Oy | Energy | 1965 |
| High Voltage Consulting Oy | Construction | 2016 |
| HillSivu Oy | Financial services | 2023 |
| Hillo Solutions Oy | Real estate | 1988 |
| Hionta ja Koneistus HS Oy | Other services | 2015 |
| Hitsauspalvelu J. Koivumäki Oy | Construction | 1998 |
| Hitsipori Oy | Wholesale & retail | 1998 |
| Hius- ja kauneushoito Ruby Oy | Other services | 2004 |
| Hobby Bonus Oy | Information & communication | 2021 |
| Hobitti Invest Oy | Real estate | 2021 |
| Hocus Pocus Meal Oy | Hospitality | 2024 |
| Hoitola Höyhen Oy | Other services | 2022 |
| Hoitolinja 2000 Oy | Wholesale & retail | 1995 |
| Hoivapalvelu Blom Oy | Health & social care | 2025 |
| Holding Oy Porin Kehitys | Financial services | 2015 |
| Holmstrom Enterprises Oy | Professional & scientific | 2025 |
| Holospac Oy | Financial services | 2026 |
| Holpin Oy | Education | 2024 |
| HomeTaisto Oy | Professional & scientific | 2019 |
| Honkaluoto-Kiinteistöt Oy | Real estate | 1978 |
| Honkatech Solutions Oy | Professional & scientific | 2024 |
| Hoosat Oy | Information & communication | 2023 |
| Hopeaviittoma Oy | Professional & scientific | 2024 |
| Hostel Buisto Ky | Real estate | 2004 |
| Hotelli-Ravintola Rantakartano Oy | Hospitality | 1990 |
| Hovinvest Oy | Real estate | 2020 |
| Hubble Oy | Information & communication | 2017 |
| Hubi Oy | Information & communication | 2023 |
| Hugel Oy | Construction | 2020 |
| Huhtala Invest Oy | Transport & logistics | 2020 |
| Huhtalan Tallit Oy | Real estate | 1997 |
| Huhtaware Digital Oy | Professional & scientific | 2025 |
| Huhtaware Oy | Professional & scientific | 2016 |
| Humandigi Oy | Professional & scientific | 2016 |
| Hunt Pori Oy | Hospitality | 2025 |
| Hunter's Kiinteistöt Oy | Real estate | 2022 |
| Huolto Group Oy Pori | Manufacturing | 2014 |
| Huolto Lepistö Lift Systems Oy | Construction | 2024 |
| Huolto Lepistö Oy | Construction | 2007 |
| Huolto-Mikko Oy | Transport & logistics | 1975 |
| Huoltokenno Oy | Financial services | 1995 |
| Huoltopalvelu Härkälä Oy | Transport & logistics | 2020 |
| Huoltopioneerit Oy | Other services | 2017 |
| Huoltoservice Rajala Oy | Other services | 2026 |
| Huonekalu-Linna Oy | Wholesale & retail | 1977 |
| Huonekaluliike Mööpeli Ky | Wholesale & retail | 1980 |
| Huovinvest Oy | Financial services | 2017 |
| Husmur Invest Oy | Real estate | 2021 |
| Huurak Oy | Construction | 2013 |
| Huvilajuovan vesiosuuskunta | Water & waste | 2008 |
| Hydol Oy | Manufacturing | 1985 |
| Hydro Import TT Ky | Wholesale & retail | 1991 |
| Hydroala Oy | Manufacturing | 2020 |
| Hynninen transport oy | Transport & logistics | 2025 |
| Hypori Oy | Financial services | 2025 |
| Hyttisen Eristysliike Oy | Construction | 1964 |
| Hyveläntien Eläinklinikka Oy | Professional & scientific | 2017 |
| Hyviluodon-Papinluodon vesiosuuskunta | Water & waste | 2015 |
| Hyvinvointikeskus Olennainen Oy | Real estate | 2019 |
| Hyvinvointimyymälä SaRa Oy | Wholesale & retail | 2016 |
| Hyvinvointitekijät Oy | Health & social care | 2025 |
| Hyvät Ideat Ky | Professional & scientific | 1983 |
| Hyyrykoski Oy | Construction | 2025 |
| Hyötyjätkä Oy | Administrative & support | 2007 |
| Hyötytuuli Services Oy | Professional & scientific | 2024 |
| Hä-yhtiö Oy | Construction | 2019 |
| I&K Rakennus Oy | Construction | 2016 |
| IB Media Oy | Professional & scientific | 2021 |
| Idmi OY | Professional & scientific | 2024 |