Sicily is the largest island in the Mediterranean Sea with a total area of 25,469 square kilometers and a population of 5 million. The second largest is Sardinia with a collected total area of 23,813 square kilometers and with 1.6 million people living on it.
There are a few possible answers to that. The island of Crete is in the Mediterranean Sea, which is part of Greece. The island of Cyprus is a full country in the Mediterranean Sea. Turkey is on the other side of the Mediterranean Sea.
Cyprus is the largest island country, although the northern section is occupied by Turks who declared their own sovereignty. The two larger islands in the Mediterranean are Sicily and Sardinia, both part of Italy.