These ships were enlarged and improved versions of the preceding Astraea class.

To reduce biofouling, the hulls of the ships were sheathed with wood and copper.

Using normal draught, the boilers were intended to provide the engines with enough steam to generate 8,000 indicated horsepower (6,000 kW) and to reach a speed of 18.5 knots (34.3 km/h; 21.3 mph); using forced draft, the equivalent figures were 9,600 indicated horsepower (7,200 kW) and a speed of 19.5 knots (36.1 km/h; 22.4 mph).

During their sea trials, all of the lightly loaded ships exceeded their specifications and reached a top speed of 20 knots (37 km/h; 23 mph).

One gun was mounted on the forecastle, two on the quarterdeck and one pair was abreast the bridge.

[10] The primary protection of the Eclipse class was its sloping armoured deck.