'Ostpreussen' was a German naval diversionary operation in tandem with 'Westfalen' in support of 'Beowulf II' (12/13 October 1941).

The operation was undertaken by the motor minesweepers of Korvettenkapitän Jost Brökelmann’s 2^nd Räumboots-Flottille on the eastern side of the Estonian island of Hiumaa (Dagö in German) in the mouth of the Gulf of Riga and, like 'Westfalen', helped to tie down Soviet forces which could otherwise have been redeployed to counter the real German landing, which was committed on the island’s south coast.