At Helsinki Airport, there are service desks for the following car rental companies: Alamo, Avis, Budget, Enterprise, Europcar, Hertz, National and Sixt. Service desks can be found from terminal arrivals hall. Please check the contact details for the companies from Finavia's web page or from each company's own web page.
There are other companies nearby the terminal building at Helsinki Airport, such as Add car at Hotel Scandic and Firent at St1 gas station. Information about these can be found from car rental companies own web pages.
If you wish to rent a car from some other airport in Finland, please check the contact details from airport specific web page.