The Amvrakikos Gulf is one of the largest closed bays of Greece. The entrance of the bay is in the narrow passage between Aktio (on the side of Aitoloakarnania) and Preveza. The bay is named after ancient Amvrakia, a town built on the river Arhathos, in the place of today’s Arta. The rivers Louros and Arachthos flow into the bay. At Amvrakikos is built Amfilochia. Near Amfilochia is the cape of St. George, where there is a lighthouse. Vonitsa is also another important town on the road from Amfilochia to Preveza and Lefkada.
At the entrance of the bay, a submarine tunnel was constructed and launched in 2002, connecting Aktio with Preveza . In the bay and especially in the port of Amfilochia, during the summer months (especially in August), the phenomenon of phosphorescence of the sea, which is due to the accumulation of microorganisms (plankton).