Located on the main road to the vital port of Vyborg, the town of Porlampi was occupied by the Soviets in March 1940 following the Battle of Summa.

[4] Following the end of the Winter War in March 1940, Finland was forced to cede part of Karelia to the Soviet Union, with Porlampi being one of the territories handed over.

On 29 June Carl Gustaf Emil Mannerheim, Marshal of Finland, formed the Army of Karelia under the command of Erik Heinrichs.

The Soviet 23rd Army withdrew some of its divisions from the Finnish border, seeking to use the narrow part of the Karelian Isthmus to better utilize their numerical superiority for defense.

The Finnish plan had been modified as the situation changed; rather than assault Vyborg, the IV Corps would now maneuver around the northern flank of the city and pursue the withdrawing Soviets to the Vuoksi River.

[3][9] The main body of the Finnish IV Corps crossed the border to the north of Vyborg on 22 August, and continued to advance towards the Vuoksi River in the opening days of the offensive.

On 24 August the Finnish 8th Division crossed Viipuri Bay, landing to the south of Vyborg and cutting the coastal road to the city.

Though heavily outnumbered, Finnish Light Brigade T stalled the Soviets for a few crucial hours while IV Corp advanced southward on 25 August.

[11] For the next few days both armies drew up their forces and prepared for an engagement in the heavily forested terrain around the town of Porlampi, which was positioned between the coastal and central Karelian highways.

[12] In the several days of fighting that ensued in the Porlampi area, the Finns employed motti skirmishing tactics to counter the superior Soviet numbers.