"Islands in their natural state (natural harbours) with waste disposal facilities and mooring rings have been reserved for boaters.
Based on the Scandinavian public right of access, it is permitted to use natural harbours temporarily for sleeping overnight, for resting or for swimming. This also applies to other islands that are not preserved for some special reason, as long as this does not harm or disturb other people. Mooring or anchoring at a private jetty or off the shore of private homes or in their immediate vicinity (100-200 m) is not permitted. This also applies to harbours reserved exclusively for members of a boat club. It is permitted to walk on private property, roads and paths, but not in yards, fields, meadows, or newly planted forests. Upon departure, the public right of access requires that you leave the area in its natural state and as untouched as possible.
On the Finnish coast and inland waterways the water quality is good and in general it is possible to swim anywhere. Blue-green algae may occur at certain times.
Public right of access is not prescribed by law. Increasing tourism could bring on pressures to examine the public right of access, but utilizing the right with discretion can reduce these pressures."

Copied from "Finska Sjöfartsverkets" homepage on public right of access.

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