Coast guard vessels were seeking five undocumented immigrants who went missing early on Saturday off the coast of Gera on the island of Lesvos in the northeastern Aegean Sea.
The rescue operation was launched by the Merchant Marine Ministry following a call from another immigrant on the same day alleging that he and a group of about 50 people were onboard a rudderless boat.
Forty-five migrants were subsequently located on shore.
Greece is a key point of entrance and transit for migrants wishing to travel to other European destinations.
Twelve undocumented immigrants drowned off the island in February when their boat sank after traveling illegally from Turkey.