- 1 December 1939 a short firefight between the Russarö fort (6 * 254 mm/50-BS , 6 * 75 mm/50-CM) and a soviet Task Force of cruiser Kirov accompanied by two class G destroyers. One of the destroyers was damaged and the soviet forces withdrew.
- 14 December 1939 a short firefight between the Utö fort (4 * 152 mm/45-C) and two soviet class G destroyers, which ended when a hit was spotted and the destroyers withdrew behind a smokescreen. Through the smoke explosions were seen and heard , and after the smoke dissipated only one destroyer was seen afloat.
- on 18 and 19 December 1939, a strong Soviet Task Forces led by battleships Marat and Oktjabrskaja Revolutsija bombarded the Saarenpää fort (6 * 254 mm/45-D , 2 * 152 mm/45-C) with the help of dozens of fighters and bombers. The Oktjabrskaja Revolutsija attacked on 18 December and Marat on the next day. The bombardment on the second day ended at 12.55 A.M., when a hit was seen on Marat's stern and it stopped firing and withdrew.
The Finnish fort suffered heavy material damage and some personnel casualties, but it was not knocked out.