Operation Albion was a World War I German air, land and naval operation against the Russian forces in October 1917 to occupy the West Estonian Archipelago. The land campaign opened with German landings at the Tagalaht (Tagga) bay on the island of Saaremaa (Ösel), on 12 October, after extensive naval operations to clear mines and subdue coastal artillery batteries. German forces secured the island by 16 October and the Russian army evacuated Muhu (Moon) on 20 October.

Saaremaa is the largest and most populous island in Estonia. Measuring 2,673 km2 (1,032 sq mi), its population is 31,435. The main island of the West Estonian archipelago, it is located in the Baltic Sea, south of Hiiumaa island and northwest of the Gulf of Riga. The administrative centre of the island, and of the Saare County, is the town of Kuressaare, which in January 2018 had 13,276 inhabitants.