Savonlinna is easily to reach by plane or train from Helsinki:
Tiny Savonlinna Airport (IATA: SVL) is served by Flybe, which offers flights from Helsinki to Savonlinna up to two times per week day. There is a shuttle service to and from the bus station, which departs one hour before the flight leaves.
There are 3-4 trains daily from Helsinki or Joensuu to Savonlinna. The trip to Helsinki takes about 4 and half hours. The main train station in Savonlinna is next to the market square.
Helsinki is easily accessible, no matter from where you are travelling from, and is served by many international flights. In Helsinki-Vantaa airport there are various rental car companies available. If you want to travel with your own car, you can reach Helsinki via ferry from Tallinn, Stockholm, Travemünde and Rostock.
Text & Pictures in Dropbox