Before she was transferred to the Eastern Mediterranean in May 1915, Dupleix spent most of her time on escort duty in the Indian Ocean and Red Sea.

The engines of all three ships were designed to produce a total of 17,100 metric horsepower (12,600 kW) that was intended to give them a maximum speed of 21 knots (39 km/h; 24 mph).

[3] The ships of the Dupleix class had a main armament that consisted of eight quick-firing (QF) Canon de 164.7 mm Modèle 1893–1896 guns.

[1] The nickel steel armor belt of the Dupleix-class cruisers covered the entire waterline length of the ship except for 18.9 meters (62 ft)[4] of the stern.

[8] Upon completion the ship became flagship of the Atlantic Division, visiting the Azores, West Africa and the Americas before she was reduced to reserve in 1906.

The following day she joined the British pre-dreadnought battleship HMS Triumph as she steamed north to begin the blockade of the German-leased port of Qingdao.

She developed engine problems which prevented her from joining the search for the German light cruiser SMS Emden once the Imperial Japanese Navy assumed responsibility for the blockade on 9 September.

On the 26th, the cruiser was attacked by Ottoman coastal artillery at Bodrum while inspecting shipping, losing 27 men killed and 11 wounded.

The successes of German merchant raiders like Möwe in 1916 caused the Allies to transfer cruisers to the Atlantic to protect their shipping.

[11] To release manpower for higher-priority patrol boats, the 6th DL was reduced to Dupleix and Desaix and renamed the Coast of Africa Division (Division navale de la côte d'Afrique) on 18 May 1917; Contre-amiral (Rear Admiral) Louis Jaurès transferred his flag to Dupleix.