There are trains (and buses, but I have no experience with them) going from HEL to Helsinki Central Railway Station in the city centre (Helsingin päärautatieasema). The trains take 25-30 minutes and both lines (I and P) go every 10 minutes. Information on the train is also given in english. One-way adult tickets are 5.50, 24h tickets for the region (including Helsinki, Vantaa, Espoo and Kauniainien) is 12 Euro. Tickets can be bought at the baggage claim area within the airport, at the train stations themselves (airport and railway station) or from a conductor in some trains (trains are marked, if there is or is no ticket sale available on the train or in which carrier). More information esp. on prices and timetables can be found here: https://www.hsl.fi/en/timetables-and-routes/terminals/transport-links-helsinki-airport . It is worth exploring the city of helsinki, if you have a longer layover.
Ground transportation to Helsinki
đź”— Sat, 03 Dec 2016
— @lesles at Helsinki Vantaa Airport, Finland
There are trains (and buses, but I have no experience with them) going from HEL to Helsinki Central Railway Station in the city centre (Helsingin päärautatieasema). The trains take 25-30 minutes and both lines (I and P) go every 10 minutes. Information on the train is also given in english. One-way adult tickets are 5.50, 24h tickets for the region (including Helsinki, Vantaa, Espoo and Kauniainien) is 12 Euro. Tickets can be bought at the baggage claim area within the airport, at the train stations themselves (airport and railway station) or from a conductor in some trains (trains are marked, if there is or is no ticket sale available on the train or in which carrier). More information esp. on prices and timetables can be found here: https://www.hsl.fi/en/timetables-and-routes/terminals/transport-links-helsinki-airport . It is worth exploring the city of helsinki, if you have a longer layover.