The arc itself is mainly marine, the mountaintops appearing as islands in the Ionian Sea, Crete and its environs, or in the Dodecanese group.

It encroaches on mainland terrain in the Peloponnesus, on Crete, on Rhodes, and on the southern coast of Anatolia, thus being encompassed by both Greece and Turkey.

It so happens that, due to back-arc extension, the Hellenic Arc and Trench are moving in the reverse direction, from inner to outer, accounting for the severe arcuate form.

The current geometry of the Hellenic arc is a result of the southwards migration of the subduction zone.

The Hellenic arc is one of the most active seismic zones in western Eurasia.