| Iceberg Distribution AS | Wholesale & retail | 2026 |
| Idiograph AS | Information & communication | 2026 |
| Iek Holding AS | | 2018 |
| Ihh AS | | 2023 |
| Ikaro AS | Professional & scientific | 1994 |
| Ikt Partner Nord Da | Information & communication | 2003 |
| Iku AS | Administrative & support | 1992 |
| Ilder Invest AS | | 2025 |
| Ildstedet Tromsø AS | Wholesale & retail | 2009 |
| Iles AS | Hospitality | 2024 |
| Ilux AS | Wholesale & retail | 1992 |
| Imera AS | Real estate | 2008 |
| Imi Tromsø Begravelsesbyrå AS | Other services | 1951 |
| Imi Tromsø Eiendom AS | Real estate | 2014 |
| Impeto AS | Construction | 2005 |
| Impeto Eiendom AS | Real estate | 2011 |
| Impit Solutions AS | Information & communication | 2025 |
| Impuls Teknisk AS | Manufacturing | 2026 |
| In Balance Inventions AS | Manufacturing | 2022 |
| Indahl Fiskebåt AS | Agriculture & fishing | 2017 |
| Indahl Star AS | Agriculture & fishing | 2009 |
| Indahl Star II AS | Agriculture & fishing | 2013 |
| Indre Troms Invest AS | Manufacturing | 2020 |
| Indreberg Tours AS | Arts & recreation | 2025 |
| Industrielle AS | Construction | 2017 |
| Industripersonell AS | Administrative & support | 2022 |
| Industripersonell Marine AS | Professional & scientific | 2022 |
| Info-Sys AS | Professional & scientific | 1987 |
| Ing Inst F. Isaksen AS | Construction | 2006 |
| Ing Åge Jensen AS | Professional & scientific | 1997 |
| Ing. Geir Kilmark AS | Real estate | 2007 |
| Ingel Invest AS | Professional & scientific | 2008 |
| Ingenii AS | Information & communication | 2023 |
| Ingeniørene Guttormesen Og Solberg Da | Professional & scientific | 2003 |
| Inger Klo Holding AS | | 2021 |
| Ingrid Krokvik Birkelid | Arts & recreation | 2013 |
| Ingyjaco AS | Wholesale & retail | 2025 |
| Ingyjaco Holding AS | | 2026 |
| Ink & Fades Jekta AS | Other services | 2017 |
| Innfra AS | | 2026 |
| Innovation Garage AS | Information & communication | 2016 |
| Innovation Group AS | Professional & scientific | 2020 |
| Inor AS | Professional & scientific | 2004 |
| Insales AS | Administrative & support | 2013 |
| Inspire Yogastudio AS | Education | 2014 |
| Installasjon Og Salg AS | Construction | 1992 |
| Installere Elektro AS | Construction | 2022 |
| Institutt for Manuell Terapi AS | Health & social care | 1991 |
| Instorier AS | Information & communication | 2022 |
| Integrale AS | Real estate | 2002 |
| Integralis AS | Professional & scientific | 2018 |
| Inter Entertainment AS | Information & communication | 2024 |
| Interiørstudio Tromsø AS | Wholesale & retail | 2018 |
| International Matsenter AS | Wholesale & retail | 1991 |
| Intersport Tromsø - Torgsenteret AS | Wholesale & retail | 2023 |
| Intety AS | Information & communication | 2020 |
| Intimate Da | Arts & recreation | 2004 |
| Invelis Capital AS | | 2019 |
| Invenia AS | Information & communication | 2007 |
| Inventum Investeringer AS | Wholesale & retail | 2021 |
| Inventum Tromsø AS | Wholesale & retail | 2021 |
| Invertere AS | Information & communication | 2019 |
| Investex Holding AS | Real estate | 2005 |
| Investex Landlord AS | Real estate | 2011 |
| Investico Strategy Norge AS | Information & communication | 2020 |
| Investor Bol AS | Real estate | 2016 |
| Invidia AS | Real estate | 1998 |
| Iran Mayen Da | Arts & recreation | 2018 |
| Iris Bondø AS | Health & social care | 2022 |
| Iron Ridge Group AS | | 2026 |
| Ironfield Productions AS | Information & communication | 2025 |
| Isbråten Maskin AS | Construction | 2015 |
| Ishav Invest AS | Real estate | 2020 |
| Ishavet Eiendom AS | Real estate | 2018 |
| Ishavsbyen Bedriftshelsetjeneste SA | Health & social care | 1991 |
| Ishavsbyen Eiendom AS | Real estate | 2013 |
| Ishavsbyen Elektro AS | Construction | 2023 |
| Ishavsbyen Holding AS | Construction | 2023 |
| Ishavsportalen AS | Real estate | 2021 |
| Ishavstoget AS | Professional & scientific | 2014 |
| Ishavsvertskapet AS | Transport & logistics | 2026 |
| Ismart AS | Information & communication | 2025 |
| Isolasjonskompaniet Ikas AS | Construction | 1997 |
| Isoteam AS | Construction | 2024 |
| Isrenna AS | Real estate | 2022 |
| Isrenna Butikkdrift AS | Hospitality | 2022 |
| Isrenna Eiendom AS | Construction | 2017 |
| Isrenna Holding AS | Real estate | 2005 |
| Issa Frisør a AS | Other services | 2026 |
| Istay Invest AS | Real estate | 2022 |
| Istinden Holding AS | | 2026 |
| IT Center Da | Other services | 2002 |
| It's Gonna Happen AS | Information & communication | 2016 |
| Itacus AS | | 2011 |
| Itide Holding AS | Real estate | 2005 |
| Itkomet AS | Information & communication | 2022 |
| Ivar Aasensvei 12 AS | Real estate | 2018 |
| Iveno Holding AS | | 2025 |
| Ivinas Systue AS | Manufacturing | 2026 |
| J a Johnsen AS | Real estate | 1990 |