| Sjølund Eiendom AS | Real estate | 2000 |
| Sjølundvegen 1 AS | Real estate | 2007 |
| Sjølundvegen 7 AS | Real estate | 2023 |
| Sjømatfestivalen AS | Arts & recreation | 2019 |
| Sjøset Holding AS | | 2022 |
| SK Gruppen AS | Real estate | 2002 |
| Skaalbjorn AS | Administrative & support | 1979 |
| Skaidi Holding AS | | 2021 |
| Skansegata 2 Tromsø AS | Real estate | 2020 |
| Skansen Legekontor AS | Health & social care | 2013 |
| Skaperlaget Keramikkverksted AS | Education | 2024 |
| Skarphallen Eiendom AS | Real estate | 1994 |
| Skarphallen Fotball AS | Arts & recreation | 1994 |
| Skarsfjord Panorama SA | Real estate | 2015 |
| Skattekammer AS | Arts & recreation | 2021 |
| Skattøra 58 AS | Real estate | 2023 |
| Skattøra 62A AS | Real estate | 2023 |
| Skattøra 62B AS | Real estate | 2023 |
| Skattøra 64 AS | Real estate | 2023 |
| Skattøra 66 AS | Real estate | 2011 |
| Skattøra Industriområde Utvikling AS | Professional & scientific | 2026 |
| Skattøra Invest AS | Administrative & support | 1988 |
| Skattøra Lagerutleie AS | Real estate | 2021 |
| Skattøra Marina AS | Arts & recreation | 1996 |
| Skattøra Nord AS | Real estate | 2010 |
| Skattøravegen Utleie AS | Real estate | 2019 |
| Skattøraveien 41 AS | Real estate | 2016 |
| Skattøraveien 52 AS | Real estate | 1997 |
| Skattørvegen 25 AS | Real estate | 2025 |
| Skattørvegen 56 AS | Real estate | 2006 |
| Skeidar Tromsø AS | Wholesale & retail | 1997 |
| Skgt 35 AS | Real estate | 1985 |
| Skibootguy AS | Wholesale & retail | 2024 |
| Skills Trafikkskole AS | Education | 2018 |
| Skiltmaler Gundersen AS | Arts & recreation | 2018 |
| Skin Therapy by Leila AS | Other services | 2026 |
| Skinlab Tromsø AS | Health & social care | 2022 |
| Skippergata 1-7 AS | Real estate | 2014 |
| Skippergata 11 AS | Real estate | 2019 |
| Skippergata 15 AS | Real estate | 2016 |
| Skippergata 2 AS | Real estate | 2008 |
| Skippergata 26 AS | Real estate | 2021 |
| Skippergata 35/39 AS | Real estate | 2019 |
| Skippergata SA | Real estate | 2022 |
| Skir Brygge AS | Transport & logistics | 2024 |
| Skissefilm AS | Information & communication | 2024 |
| Skitromsø AS | Administrative & support | 2025 |
| Skivika AS | Real estate | 2019 |
| Skjelnan Bolig AS | Real estate | 2019 |
| Skjelnan Utbygging AS | Real estate | 2006 |
| Skjervøy Havn AS | Real estate | 2015 |
| Skjoldnes Hage AS | Real estate | 2018 |
| Skog Management AS | Professional & scientific | 2014 |
| Skogfaret Bærum AS | Real estate | 2009 |
| Skogøy AS | Agriculture & fishing | 2017 |
| Skoleveien 4 AS | Real estate | 2022 |
| Skotreff AS | Wholesale & retail | 1998 |
| Skrapvarde AS | Information & communication | 2022 |
| Skulbaren Mat AS | | 2026 |
| Sky Fitness Tromsø AS | Arts & recreation | 2023 |
| Skyggen AS | | 2016 |
| Skårungen Vel SA | Real estate | 2017 |
| Sleet Holding AS | | 2020 |
| Slettatorget 1 Og 8 AS | Real estate | 2018 |
| Slettmo AS | Professional & scientific | 2013 |
| Smak Nordnorsk Matfestival AS | Arts & recreation | 2012 |
| Smallsoft AS | Information & communication | 2014 |
| Smart Repair Tromsø AS | Other services | 2014 |
| Smart Repair Tromsø Da | Other services | 2010 |
| Smartcons AS | Professional & scientific | 2023 |
| Smarthotel Tromsø AS | Hospitality | 2011 |
| Smartlakkering AS | Other services | 2024 |
| Smileeyes AS | Health & social care | 2014 |
| Smørtorget AS | Hospitality | 2013 |
| Snakk for Deg Sjøl AS | Education | 2015 |
| Snakk Invest AS | Wholesale & retail | 2005 |
| Snakk Tromsø AS | Wholesale & retail | 1999 |
| Snarby Strikkestudio AS | Wholesale & retail | 1998 |
| Sne Eiendomsmegling AS | Real estate | 2018 |
| Sne Nybolig AS | Real estate | 2018 |
| Sne Næringsmegling AS | Real estate | 2016 |
| Sne Regnskap AS | Professional & scientific | 2015 |
| Sne Trading AS | Wholesale & retail | 2022 |
| Sne Utleie AS | Real estate | 2018 |
| Snekkerservice Tromsø AS | Manufacturing | 1997 |
| Snorre Art AS | Arts & recreation | 2017 |
| Snow Travels AS | Administrative & support | 2023 |
| Snö AS | Information & communication | 2017 |
| Snö of Sweden Norge Nuf | Wholesale & retail | 2008 |
| Snø Invest AS | Professional & scientific | 2021 |
| Sobota AS | Wholesale & retail | 1983 |
| Sofistikerte Beats Da | Administrative & support | 2018 |
| Softcap AS | Information & communication | 2023 |
| Solan Shipping AS | Wholesale & retail | 2021 |
| Soldagen Barnehage AS | Education | 1991 |
| Solid AS | Hospitality | 1999 |
| Solid Mannskap AS | Administrative & support | 2026 |
| Solir AS | Real estate | 2016 |
| Solkom AS | Professional & scientific | 2018 |
| Solli Trappefabrikk Salg Tromsø AS | Wholesale & retail | 2023 |