As both sides were eager to avoid a major, costly ground battle, fighting took the form of trench warfare, with artillery exchanges, sniping, patrol clashes, and small amphibious operations performed in the surrounding archipelago.

Though Mannerheim initially declared that liberating Hanko would be a primary goal of the war, Finnish troops in the area did not receive authorization to attack the base.

[3] Minefields laid on the sea lanes leading to Hanko and the surrounding waters were more effective, claiming several Soviet supply vessels.

These problems, in addition to the rapid German advance on the southern shore of the Gulf of Finland, caused the base to lose its importance and made it an untenably heavy burden for the Soviet Baltic Fleet.

As Finland lacked the resources to transport enough goods over land, this caused severe logistical problems, with material stuck in seaports on the Western coast.

The initial landing, performed in the middle of the night in foggy conditions, was successful, as Finnish sentries believed the approaching boats to be German minesweepers; however, the small garrison recovered quickly.

Putting up fierce resistance, the Finns managed to retain control of the lighthouse while summoning help from nearby naval forces and coastal artillery.

The fleet suffered losses to Finnish minefields and coastal artillery, losing three destroyers, two large transports (Andrei Zhdanov and Iosif Stalin), and several smaller vessels.