Hydra (Greek: ΒΠ Ύδρα) (sometimes spelled Ydra[1][2]) was a Greek destroyer of the Kountouriotis class, which served with the Hellenic Navy during the early stages of the Second World War.

[1] Three Yarrow Express boilers fed steam to two sets of Parsons geared steam turbines, with the machinery rated at 44,000 shp (33,000 kW), giving a speed of 38 kn (44 mph; 70 km/h).

630 long tons (640 t) of oil was carried, giving a range of 5,800 nmi (6,700 mi; 10,700 km) at 20 kn (23 mph; 37 km/h).

[1] Hydra was launched at Odero's Sestri Ponente shipyard on October 21, 1931, and was commissioned by the Hellenic Navy in November 1932.

[4] After the outbreak of the Greco-Italian War, she participated in the first naval raid against Italian shipping in the Strait of Otranto (November 14–15, 1940).