That is a peninsula.
A headland jutting out to sea can be called a cape.
Korea is located on the Korean Peninsula, which is a large landform jutting out from the Asian mainland. It is surrounded by the Sea of Japan to the east and the Yellow Sea to the west.
It is called Cape Cod.
It is called Cape Cod.
It is called Cape Cod.
It is called Cape Cod.
A narrow strip of land projecting from the mainland into a sea or lake is called a peninsula.
A piece of land joined to the mainland with three sides or more bordered by the sea is called a peninsula.
Seastack
A cape is a large piece of land jutting out into the sea. An island is completely surrounded by water.
An offshore column of rock that was once part of the mainland is called a sea stack or stack. It was formed by erosion.
In the Mediterranean Sea, in Europe. The whole of Italy is a penisula, jutting out into the sea.