The Piper Arrow light aircraft carrying the three people was en route to Helsinki-Malmi Airport when it crashed into an area of forest on the south side of Emäsalo island.
An eye witness said the plane flew into a cloud of snow, its engine stalled after which it crashed.
The crash site has been sealed off and investigators have started their enquiries. The reason for the crash is not yet known.
Aviation authority Finavia was quick to reassure the crash had no connection with the recent volcanic ash cloud.