She was initially assigned to the 1st Cruiser Squadron upon completion in 1903 and ran aground en route to the China Station in 1906.

Donegal rejoined the 4th Cruiser Squadron on North America and West Indies Station in 1917 and continued with convoy duties until the end of the war.

The Monmouths were intended to protect British merchant shipping from fast cruisers like the French Guichen, Châteaurenault or the Dupleix class.

The engines produced a total of 22,000 indicated horsepower (16,000 kW) which was designed to give the ships a maximum speed of 23 knots (43 km/h; 26 mph).

[2] The Monmouth-class ships' main armament consisted of fourteen breech-loading (BL) 6-inch (152 mm) Mk VII guns.

[9] Whilst en route to the China Station, she ran aground at Suez, Egypt on 2 March 1906[7] and had to return to Chatham Dockyard for repairs.

Donegal was transferred to the 4th Cruiser Squadron on the North America and West Indies Station in 1909[9] and collided with the merchant ship SS Malaga at Gibraltar on 8 December.

Donegal rejoined the 4th Cruiser Squadron on North America and West Indies Station in 1917 and continued with convoy duties until the end of the war.