| Huubro Holding AS | Information & communication | 2019 |
| Hvac Consult AS | Professional & scientific | 2015 |
| Hvbo Utbygging AS | Construction | 2021 |
| Hyr AS | Administrative & support | 2021 |
| Hyr Nordland AS | Administrative & support | 2023 |
| Hyr Rekruttering AS | Administrative & support | 2016 |
| Hå Byggteknikk AS | Professional & scientific | 2013 |
| Håge AS | Professional & scientific | 2016 |
| Håkestad Eliassen AS | Arts & recreation | 2022 |
| Hålogaland AS | Real estate | 1994 |
| Hålogaland Autoskade AS | Other services | 2026 |
| Hålogaland Bakeri AS | Manufacturing | 2022 |
| Hålogaland Eiendom AS | Real estate | 2007 |
| Hålogaland Elektro AS | Construction | 2001 |
| Hålogaland Festivalservice AS | Administrative & support | 2004 |
| Hålogaland Industrier AS | Manufacturing | 2005 |
| Hålogaland Invest AS | Real estate | 2016 |
| Hålogaland Kraft Holding AS | | 2020 |
| Hålogaland Økonomiforvaltning AS | Professional & scientific | 2014 |
| Hålogalandspizza AS | Hospitality | 2002 |
| Hårek Frisør AS | Other services | 1994 |
| Håribel AS | Other services | 2013 |
| Hårny AS | Other services | 1999 |
| Hårstua Harstad AS | Other services | 2010 |
| Håvard AS | Real estate | 2005 |
| Høas AS | Agriculture & fishing | 2022 |
| Høgtun 3 AS | Real estate | 2026 |
| Høybakks Intertrade AS | Wholesale & retail | 2018 |
| Høyt Nivå Harstad AS | Administrative & support | 2021 |
| Høyvik Eiendom AS | | 1997 |
| I Takt Da | Professional & scientific | 2025 |
| I Westvig Holding AS | | 2025 |
| I-A Holding AS | Wholesale & retail | 2024 |
| Iamme AS | Real estate | 1997 |
| Ib Maler Proff AS | Construction | 2016 |
| Ident Tannteknikk AS | Manufacturing | 2021 |
| Idrive AS | Education | 2013 |
| Ikm Teknor AS | Manufacturing | 2024 |
| Imalo AS | | 2022 |
| Imtas Harstad AS | Manufacturing | 2024 |
| Industri & Anlegg AS | Wholesale & retail | 1985 |
| Industri & Maling AS | Construction | 2001 |
| Industrimontasje AS | Manufacturing | 2010 |
| Industriveien 12 Andenes AS | Real estate | 2017 |
| Informatics AS | Information & communication | 2022 |
| Inge Jensa AS | | 2022 |
| Ingeniørkompaniet Ans | | 1993 |
| Inko AS | Health & social care | 1964 |
| Inko Eiendom AS | Health & social care | 2021 |
| Inko Holding AS | Health & social care | 2021 |
| Innaførr Harstad AS | Real estate | 2005 |
| Interiør Harstad AS | Wholesale & retail | 2019 |
| Interiør Narvik AS | Wholesale & retail | 2019 |
| Into Eiendom AS | Real estate | 2017 |
| IP Care AS | Administrative & support | 2023 |
| Iro Invest AS | | 2020 |
| Isabel Bruun Holding AS | | 2024 |
| Isako AS | Information & communication | 2026 |
| Ishik AS | Other services | 2026 |
| Isotec Harstad AS | Construction | 2017 |
| Isotec Holding AS | | 2025 |
| IT Partner Harstad AS | Information & communication | 2001 |
| Iver Jensa AS | Real estate | 2005 |
| J. Killi AS | | 2020 |
| J.S. Invest AS | Real estate | 2016 |
| Jacobsen Motorsport AS | Arts & recreation | 2012 |
| Jad AS | Transport & logistics | 2026 |
| Jaki Invest AS | Real estate | 2006 |
| Jakobsen Takst Og Bygg AS | Real estate | 2021 |
| Jam-Invest AS | Real estate | 2024 |
| Janne's AS | Wholesale & retail | 2003 |
| Jarle Markus Consulting AS | Professional & scientific | 2023 |
| Jas Holding AS | Professional & scientific | 2005 |
| Jass Holding AS | | 2024 |
| Jat Invest AS | Financial services | 2005 |
| JC Holding AS | Real estate | 2018 |
| Je&K AS | Real estate | 2024 |
| Je&K Holding AS | Real estate | 2024 |
| Jekki AS | Health & social care | 2019 |
| Jentoftsen AS | Administrative & support | 2023 |
| Jess Eiendom AS | Real estate | 2006 |
| JK Bygg AS | Construction | 2013 |
| Jke Design Harstad AS | Wholesale & retail | 2025 |
| JL Harstad AS | Other services | 2024 |
| JMN Invest AS | | 2022 |
| Jmo Invest AS | Financial services | 2008 |
| Jmortensen Invest AS | Professional & scientific | 2016 |
| JN Maskinservice AS | Manufacturing | 2011 |
| Job Norway Nuf | Administrative & support | 2008 |
| Jobbland AS | Professional & scientific | 2023 |
| Johanne Lilleng AS | Arts & recreation | 2026 |
| Johnnys Skrivestue AS | Arts & recreation | 2026 |
| Johnsen Transport AS | Transport & logistics | 1990 |
| Jonas Evensen | Arts & recreation | 2013 |
| Jordbærpikene Kanebogen AS | Hospitality | 2017 |
| Jostein Kajander AS | Wholesale & retail | 2023 |
| Jprd Holding AS | Real estate | 2021 |
| JTP Drift AS | Wholesale & retail | 2011 |
| Juvelen Spa & Frisør AS | Other services | 1999 |
| Juventa AS | Wholesale & retail | 2017 |