The nearest airport is the Helsinki Airport, which has good connections to all the European capitals and to the USA and Asia. The airport is 20 kilometres away from the city centre of Helsinki, and you can get there in about 30 minutes by bus.
You can take the local bus number 615 to the Helsinki Central Railway Station. The bus leaves from right outside the arrival terminals. There are also Finnair shuttle buses which also arrive at Helsinki Central Railway Station. The Finnair shuttle bus is slightly more expensive than the local bus. There are also taxis available at the airport, including some special Airport Taxis or Yellow Taxis, which have cheaper rates for groups of clients going in the same direction.
Apart from flying, you can also arrive in Helsinki by sea from Sweden, Estonia, Germany and Poland. Ferries: www.vikingline.fi, www.tallinksilja.fi, www.finnlines.com