Greece's Culture Ministry said the mission, conducted in May at depths over 120 meters by an 11-member professional diving team using closed-circuit equipment, was organized by British historian Simon Mills, founder of the Britannic Foundation, and supervised by the ministry's underwater archaeology unit.
Built alongside the Titanic and Olympic at Belfast's Harland and Wolff shipyard, the Britannic was converted into a hospital ship during World War I and sank near Kea Island in November 1916 after striking a German mine, killing 30 of the 1,065 people on board.
The recovered objects, now transferred to laboratories in Athens, will be permanently displayed in the under-construction Underwater Antiquities Museum in Piraeus.