The Roman-era sculptures were located 8ft under water in a submerged port at Mandraki, on the western side of Kythnos, a Greek island in the Cyclades.
Greece's culture ministry said the statues consisted of a stone torso of a man in armour as well as another figure - the bearded head of another man.
In a statement, the ministry said it did not yet know whether the torso and the head were both taken from the same figure, but that the torso stood 4.5ft high.
It is not clear who the statues represented.
In the past, surveys at Mandraki have uncovered piers and building material under the azure waters of the Aegean.
The latest finds were thought to have been used as building materials sometime after they were no longer wanted as statues.
The statues are thought to have been sculpted sometime during the Romans' domination of the Greek mainland from the 2nd century AD when they defeated the weakening Macedonian kingdom and some Greek city states.
The Romans ruled Kythnos, located about 60 miles southeast of Athens, until around 330 AD.