| Tammisaaren Pienet käpälät - Ekenäs Små tassar Oy | Professional & scientific | 2025 |
| Taxi-Nordström Oy | Transport & logistics | 2005 |
| Tekno-Test Ab | Manufacturing | 1998 |
| Tenala Byggtjänst Kb | Construction | 1988 |
| Tenala Företagarhus Ab | Real estate | 2008 |
| Tenala-Marina Oy Ab | Transport & logistics | 1985 |
| The Solar Company Oy | Wholesale & retail | 2020 |
| Thermotech Scandinavia Finland Oy | Construction | 1997 |
| Thrive and Grow Oy | Professional & scientific | 2025 |
| Timepiece VR Oy | Information & communication | 2021 |
| To Be Frank Ab | Hospitality | 2012 |
| Tom & Anne Storage Kb | Hospitality | 1997 |
| Tom Pöysti Programs Oy Ab | Professional & scientific | 1989 |
| TomCon Oy | Professional & scientific | 1990 |
| TomCon Plan Oy | Professional & scientific | 2022 |
| TomCon Raasepori Oy | Professional & scientific | 2022 |
| Trainium Ab Oy | Arts & recreation | 2016 |
| Transport K. Lindholm & Co Ab | Transport & logistics | 1992 |
| Transport N. Österman & Co Kommanditbolag | Transport & logistics | 1964 |
| Tri-Sport Finland Oy | Hospitality | 1992 |
| Trälunds Ved Ab | Construction | 2022 |
| Tunturikadun Tili, Niku-Paavola & Co Oy | Professional & scientific | 1995 |
| Turkukiinteistöt Oy | Real estate | 2003 |
| Utk - Yhtiöt OY | Education | 2016 |
| Uudenmaan Siivousmestarit OY | Administrative & support | 2025 |
| VN VVS & Energi AB - Lu Lvi & Energia OY | Construction | 2019 |
| Valdemar Group Ab | Administrative & support | 2020 |
| Venevici Ab | Manufacturing | 2022 |
| Venture Fishing Oy | Administrative & support | 2018 |
| Vesterby Värme Ab | Administrative & support | 1981 |
| Viestintä M. Saari Oy | Information & communication | 1996 |
| Virginbay Oy | Financial services | 2022 |
| Virranvuo Oy | Wholesale & retail | 2004 |
| Vitrine studio oy | Wholesale & retail | 2021 |
| Vocoi Ab | Wholesale & retail | 2021 |
| VuoriStudio OY | Professional & scientific | 2026 |
| Västerby Skidcentrum Oy Ab | Arts & recreation | 1992 |
| Västra Nylands Måleritjänst ab | Construction | 2020 |
| Västra Nylands Plåtslageri Ab | Construction | 2015 |
| Västra-Nylands Elektro-Team Oy Ab | Construction | 1995 |
| Wl-Logistics OY | Transport & logistics | 2011 |
| Wenberg Ab | Professional & scientific | 2020 |
| West-Drivers Ab Oy | Education | 2017 |
| WestLeaf öppet bolag | Administrative & support | 2012 |
| Westatus Oy Ab | Real estate | 2009 |
| Wester Contract Oy Ab | Construction | 2018 |
| Westerby Kiosk Kb Ky | Wholesale & retail | 1983 |
| Wi-Box Bageri Öb | Manufacturing | 2024 |
| Wild Shoe Oy Ab | Wholesale & retail | 1996 |
| Wina Oy | Hospitality | 2026 |
| WorkRelax Oy Ab | Administrative & support | 2015 |
| XInvest Oy Ab | Administrative & support | 2019 |
| Xiter Ab | Wholesale & retail | 2019 |
| goPADEL Ab | Arts & recreation | 2020 |
| lilla Gallerian öppet bolag | Wholesale & retail | 2023 |
| systerÅbror Ab Oy | Hospitality | 2021 |
| uFirst Investments Oy | Real estate | 2021 |
| via Garden Oy | Professional & scientific | 2008 |
| Återbruk Ab | Real estate | 1973 |
| Öhberg-Grönlund Kb | Wholesale & retail | 2016 |
| Öppet bolag Anita & Mikaela Avoin yhtiö | Wholesale & retail | 2000 |
| Öppet bolag Ekenäs Klipphörnan | Other services | 1999 |
| Öppet bolag Västra Nylands TN-Konsult Avoin yhtiö | Construction | 1991 |
| Öppna bolaget K. Huldin Avoin yhtiö | Transport & logistics | 1998 |
| Öppna bolaget Sandnäsudd K-butik Avoin Yhtiö | Wholesale & retail | 1993 |