The sea surrounding Finland is extremely favourable for mine laying: the water is shallow, there are innumerable straits and most of the coastline is dotted with islands. During the Second World War, some 60,000 mines were laid in the Gulf of Finland alone. At the time, both contact and impulse mines were already in use.

Naval mines play an important role in the Finnish defence system. The threshold of an attack against Finland can be raised substantially by laying mines at an early stage when war threatens. Protective mine barrages laid out in open sea are specially intended to protect the Helsinki area and the Åland islands. Potential landing routes can be closed efficiently with mine barrages in key straits.

The mine-laying capacity of the Finnish Navy has been improved considerably in recent years. Its Pansio class minelayers and especially the Hämeenmaa class minelayers are among the best in the world.