The Sunda Arc is a volcanic arc that has produced the islands of Sumatra and Java and the Sunda Strait and the Lesser Sunda Islands. A chain of volcanoes forms the topographic spine of these islands. The arc marks an active convergent boundary between the East Eurasian plates that underlie Indonesia, especially the Sunda Plate and the Burma Plate, and the Indo-Australian Plate that also forms the seabed of the Indian Ocean and the Bay of Bengal. The Sunda Arc is a classic example of a volcanic island arc, in which all the elements of such geodynamic features can be identified.

The India Plate is subducting under its northeast boundary. The tectonic deformation along this subduction zone in the Sunda Trench caused the 2004 Indian Ocean earthquake, December 26, 2004.