Sardegna.
The Bahamas.
ICELAND
That is Puerto Rico.
If you meant 18 degrees north latitude and 77 degrees west longitude, then the island is Jamaica. And, Nairobi is the capital of Kenya, and Kenya is not an island. Kenya is located in Africa.
St. Ives is located near 50.2 degrees N latitude, 5.5 degrees W longitude. It is located near the southwesternmost point of the island of Great Britain.
The latitude of Bainbridge Island is 47.6553 degrees north. The longitude is 122.535 degrees west. Bainbridge Island is located in Kitsap County, Washington.
Tasmania
Iceland.
The island of Hawaii.
The Philippines
Gotland, the largest island in the Baltic Sea.
San Nicolas Island is located at 33.2500 degrees north and 119.5000 degrees west.
Bornholm, a Danish island.
Riesco Island, Chile.
The Bahamas.
There is no island located at these coordinates. The Free and Sovereign State of Sonora in Mexico is found here.
Ellesmere Island and Greenland.