The Third class cruisers displaced 2,135 tons, had a crew complement of 224 men and were armed with eight QF 4 inch (102 mm) (25 pounder) guns, eight 3 pounder guns, three machine guns, and two 18 inch (450 mm) torpedo tubes.
HMS Prometheus was laid down at Earle's Shipbuilding, Hull, in 1897, launched on 20 October 1898, and moved to Sheerness to be fitted with arms in 1899.