Walfisch is an uninhabited German island, in the Bay of Mecklenburg in the Baltic Sea.

It lies approximately 4.5 kilometres (2.8 mi) north of the city of Wismar, south of the island of Poel.

The island is very flat and has a maximum circumference of about 500 by 300 metres (1,640 ft × 980 ft), a surface area of 20 hectares (49 acres) and is a nature reserve.

During the Thirty Years' War there was a fortress located on the island, which today is mainly under water.

[1] The fortress of Walfisch was destroyed in the year 1717 after the Northern Wars.