[5] It was established on 7 April 1945, from the parts of the territories of the Pomeranian Voivodeship, and the Masurian District, Poland.

The decree to establish the voivodeship had been signed on 30 March 1945, the day that Soviet and Polish forces captured the city of Gdańsk, during the Siege of Danzig, in the final months of the World War II.

[1][6] Upon its creation, it incorporated the counties from the prewar Pomeranian Voivodeship and the Free City of Danzig, both merged during occupation into the Reichsgau Danzig-Westpreußen.

However due to the heavy destruction of the city during the conflict, for the first few months of voivodeship existence, its de facto seat of government was located in nearby city of Sopot, before it was transferred to Gdańsk, later that year.

[5] Upon dissolution of the Masurian District on 25 September 1945, Gdańsk Voivodeship incorporated its part containing the territories of the former Regierungsbezirk Westpreußen, namely the counties of Elbląg, Kwidzyn, Lębork, Malbork, and Sztum, as well as the counties of Bytów, Miastko, Sławno, and Słupsk from the District of the Western Pomerania.