According to the Athens Geodynamic Institute, the first quake occurred off the holiday island of Kos in the eastern Aegean at 11:11 am, followed by the second near the island of Alonissos, in the central Aegean at 9:53 pm.
The two earthquake was felt in many nearby islands of eastern Aegean. Many people rushed out of their homes in shock.
Local police officials said there were no reports of injuries or damage to buildings.
Earthquakes are common in Greece and in neighbouring states.
Greece is a country in southeastern Europe. It has the tenth longest coastline in the world, featuring a vast number of islands.