Linois's expedition to the Indian Ocean was a commerce-raiding operation launched by the French Navy during the Napoleonic Wars. Contre-Admiral Charles-Alexandre Durand Linois was ordered to the Indian Ocean in his flagship Marengo in March 1803 accompanied by a squadron of three frigates, shortly before the end of the Peace of Amiens. When war between Britain and France broke out in September 1803, Marengo was at Pondicherry with the frigates, but escaped a British squadron sent to intercept it and reached Isle de France (now Mauritius). The large distances between naval bases in the Indian Ocean and the limited resources available to the British commanders in the region made it difficult to concentrate sufficient forces to combat a squadron of this size, and Linois was subsequently able to sustain his campaign for three years. From Isle de France, Linois and his frigates began a series of attacks on British commerce across the Eastern Indian Ocean, specifically targeting the large convoys of East Indiamen that were vital to the maintenance of trade within the British Empire and to the British economy. Although he had a number of successes against individual merchant ships and the small British trading post of Bencoolen, the first military test of Linois squadron came at the Battle of Pulo Aura on 15 February 1804. Linois attacked the undefended British China Fleet, consisting of 16 valuable East Indiamen and 14 other vessels, but failed to press his military superiority and withdrew without capturing a single ship.
In September 1804, Linois attacked a small British convoy at Vizagapatam in the Bay of Bengal and captured one ship, but was again driven off by inferior British forces. The damage Marengo suffered on the return to Isle de France was so severe that she had to be overhauled at Grand Port, and after subsequent cruises in the Red Sea and in the central Indian Ocean, where Linois was again driven away from a large British convoy by inferior British forces, he attempted to return to Europe via the Cape of Good Hope. On the return journey, Linois's ships sailed into the cruising ground of a British squadron participating in the Atlantic campaign of 1806 and was captured by overwhelming forces at the action of 13 March 1806, almost exactly three years after leaving France. Linois's activities in the Indian Ocean had caused panic and disruption across the region, but the actual damage inflicted on British shipping was negligible and his cruise known more for its failures than its successes. In France, Napoleon was furious and refused to exchange Linois for captured British officers for eight years, leaving him and his crew as prisoners of war until 1814.