Sobieszewo Island (Polish: Wyspa Sobieszewska; Kashubian: Sobieszewsczi Òstrów; formerly German: Bohnsack) is an island on the Baltic Sea, between the Gdańsk Bay and the delta of Vistula river.

The island is part of the territory of the city of Gdańsk, Poland.

The northern border of the island is the waters of Gdańsk Bay, while its southern border is a branch of the Vistula river, called the Martwa Wisła.

The western border was created in 1840 during the flooding and creation of a new mouth of the Vistula called Śmiała Wisła.

The eastern border was dug in 1895 as a new, artificially created mouth of Vistula, called Przekop Wisły.