The name of Port Edgar derives from the suggestion that in 1068, King Edgar Aetheling, while fleeing the English Normans, landed here to seek refuge in the court of Malcolm III. He came with his sister, Princess Margaret, who later married the Scottish king.
In 1810 a dock was erected in Port Edgar and began to function as a fishing port and ferry. King George IV embarked in the harbor in 1822 on a visit to the Earl of Hopetoun.
The Admiralty acquired Port Edgar in 1916 and commissioned it as HMS Columbine, establishing it as a base for the destroyers. This ended in 1928 and the site buildings were temporarily used as a holiday camp during the 1930s for the unemployed families of Edinburgh and Glasgow.
With the advent of World War II, the Royal Navy returned to Port Edgar in 1939, commissioning it as HMS Lochinvar, a mining facility. In preparation for D-Day, a combined operational training center was created in 1943 to prepare the landing craft and their crews. In the post-war period, it continued as a training center for mine diggers, housing several ships for mine warfare and testing the last dredging equipment until its closure in 1975.
In 1978, Port Edgar was acquired by the former Lothian Regional Council, which developed the site into a marina and a sailing school.
