You can travel to Vallisaari Island by water buses from Market Square, or use the Western archipelago route from Espoo to Helsinki. The routes are run by FRS Finland.
The regular ferry service to Vallisaari Island runs from the Market Square’s Keisarinluodonlaituri pier. The ferry ride takes about 30 minutes. On Vallisaari Island, the ferries arrive at Luotsipiha and depart from Torpedolahti.
You can buy ferry tickets online, onboard the water buses, and at the ticket booth at Market Square.