Harbor Astakou is open SE. It is sheltered from swells caused by S winds by a mole extending SE for 166 m, 8.4 m wide and 1.4 m high, with a parapet on its outer side and protective natural boulders. About 260 m W of the root of the mole, there is a curved jetty extending SE for 90 m and then NE for 40 m. The mole is used by local fishing vessels.
At a distance 0,2 miles SW from the curved jetty at the place (Chovolio) a mole has been constructed. The mole extents about 40 m SE. The inner part of the mole is quayed with depths from 6 m at the head up to less than one meter at the root. The coasts of the harbor are quayed for 120 m; farther E the quay has been widened in the shape of a trapezium 48 m long and it has two ramps.
Kastos is located close to larger and long-established boating and holiday home destinations such as Ithaca, Kefalonia, Lefkada and Meganissi; it is separated from its neighbouring island of Kalamos by a deep channel. Just eight kilometres long and, even at its widest, only 1,200 metres across, Kastos has a huge appeal to all forms of boating and yachting enthusiasts.