Cava takes its name from the Old Norse Kálf-ey, meaning Calf Island.
The island hit the headlines twice in the 18th century; once for the murder of James Inksetter, and once when the Orkney pirate John Gow kidnapped two girls and later deposited them on Cava.
The ships of the impounded German High Seas Fleet were arranged around Cava in a horseshoe formation shortly before the scuttling in 1919. At the time the island was owned by Cyril Kinmont, a lemonade manufacturer from Leamington Spa, who also owned Swona and Copinsay.
During WWII there were two searchlight emplacements on Cava, as well as two barrage ballons. During severe gales in the winter of 1943/4, one balloon was blown away, taking with it the cast iron winch to which it was attached.
The 1931 census lists 14 people living on Cava, but the island was depopulated in the 1940s. There was a brief period of repopulation when two ladies from the south of England made their home there, but no-one has lived on Cava since the 1980s.
The cast-iron lighthouse was replaced in 1988 with the current fibreglass model.