The ships were ordered from France in 1885 during the premiership of Charilaos Trikoupis, as part of a wider reorganization and modernization of the Greek armed forces, which had proved themselves inadequate during the Cretan uprising of 1866.

Modernizations in the 1890s and 1900s upgraded the ships' armament, but by the First Balkan War, they were too slow to keep up with newer vessels in the Greek fleet, particularly the armored cruiser Georgios Averof.

The Balkan crisis that started with the Serbo-Bulgarian War, coupled with Ottoman naval expansion in the 1860s and 1870s, prompted the Greek Navy to begin a rearmament program.

In addition, the Greek fleet had proved to be too weak to effectively challenge Ottoman naval power during the 1866 Cretan Revolt.

The ships were powered by a pair of triple expansion steam engines with four double-ended cylindrical boilers; they were rated at 6,700 indicated horsepower (5,000 kW) and provided a top speed of 17 knots (31 km/h; 20 mph).

Under a full load, however, the belt was completely submerged below the waterline, rendering it largely ineffective.

[6] Hydra was built by the Ateliers et Chantiers de la Loire dockyard in St. Nazaire, while Spetsai and Psara were built at the Société Nouvelle des Forges et Chantiers de la Méditerranée shipyard in Graville.

The Ottoman Navy had remained in port during the conflict, but a major naval intervention of the Great Powers prevented the Greeks from capitalizing on their superiority.

[4] The three ships saw action during the First Balkan War in 1912 at the Battle of Elli, alongside the powerful armored cruiser Georgios Averof.

At the subsequent Battle of Lemnos, the ships were left behind due to their slow speed and did not engage the Ottoman flotilla.

They were already obsolete and were decommissioned immediately after the war, although their hulks survived as naval training facilities and accommodation space for a decade.