The action of 3 July 1810 was a minor naval engagement of the Napoleonic Wars, in which a French frigate squadron under Guy-Victor Duperré attacked and defeated a convoy of three British East Indiamen near the Comoro Islands. Both sides suffered 20 or more sailors killed before two East Indiamen surrendered. These were Ceylon and the British flagship Windham, which held off the French squadron long enough for the ship Astell to escape. It was the third successful French attack on an Indian Ocean convoy in just over a year, and the second time the French had captured Windham. The French frigates were part of a squadron operating from the Isle de France under Commodore Jacques Hamelin.

Although a British frigate squadron under Josias Rowley was under orders to eliminate the French raiders, Rowley was distracted by the planned invasion of Isle Bonaparte, which began the following week. Combined with limited British resources in the region, this allowed the French frigates significant freedom to attack British interests across the Ocean. The attack on Isle Bonaparte was however part of a wider British strategy to seize and capture French raiding bases, and the success of the operation severely limited future French operations as Hamelin's squadron was required for the defence of Isle de France. As a result, this was the last successful attack on a British merchant convoy in the Indian Ocean during the Napoleonic Wars.

Since the beginning of the Napoleonic Wars in 1803, French privateers and naval frigates operating from the fortified island bases of Isle de France and Isle Bonaparte had attacked British shipping in the Indian Ocean. The huge distances involved, restrictions on supplies and the presence of Royal Navy warships and heavily armed East Indiamen had prevented these relatively weak French ships from attacking the convoys that transported millions of pounds worth of goods from British India and the Far East to the United Kingdom. When one French squadron under Admiral Linois had tried to seize a convoy in 1805, it had been driven off by the aggressive tactics of the merchant captains.

In late 1808, the French Navy despatched five frigates to the Indian Ocean to rendezvous at Isle de France under the command of Commodore Jacques Hamelin. Although only four frigates eventually reached the French island, these were new vessels carrying 40 heavy guns each under orders to attack British shipping in the Bay of Bengal, in particular the large East Indiamen of the Honourable East India Company (HEIC). The first frigate to do so was Caroline, which attacked a Europe-bound convoy in the action of 31 May 1809. Capturing two East Indiamen carrying over £500,000 worth of silk, Caroline brought her prizes back to the fortified port of Saint Paul on Isle Bonaparte.

The British commander at the Cape of Good Hope, Albemarle Bertie, had also been planning an operation in the Indian Ocean during 1809 and assembled a squadron under Commodore Josias Rowley with orders to blockade the French islands, probe their defences and capture them if practical. Rowley found that his small squadron was unable to engage the French frigates and that the nearest British military base, Madras in British India, was much too far away to be practical for staging amphibious operations. To remedy the latter problem, Rowley seized the small French island of Rodriguez with a force of British and Indian soldiers and garrisoned it as a supply base for his ships and as a military reserve to use in landings on the French islands. The first such operation was the Raid on Saint Paul in September 1809, in which the town of Saint Paul was captured, Caroline and her prizes seized; Isle Bourbon's commander Nicolas Des Bruslys was driven to suicide.

Despite the British attack on Saint Paul, French frigates continued to operate in the Indian Ocean, Hamelin personally leading a cruise in the Bay of Bengal during the autumn. His ships seized a number of small merchantmen and in the action of 18 November 1809 he personally defeated and captured three large East Indiamen in convoy. Before his squadron and their prizes returned to Isle de France in late December, they had also captured the British brig HMS Victor and the large Portuguese frigate Minerva. During the winter few ships were at sea, as the risk of being caught in a seasonal hurricane was considered too severe to operate between December and March. Rowley correspondingly withdrew most of his forces to the Cape of Good Hope, leaving a handful of smaller ships to watch the French islands. Hamelin too kept his forces in harbour at Isle de France, replenishing his ships and recruiting sailors from the large pool of unemployed men in Port Napoleon.

On 14 March, before Rowley could return to his blockade, Hamelin ordered a squadron to sea. This force consisted of the large frigate Bellone, the captured Minerva now renamed Minerve and the captured brig Victor. The force was led by Guy-Victor Duperré on Bellone, with Pierre Bouvet in Minerve as his second in command. Avoiding the remaining frigates of the British blockade, Duperré's ships escaped unnoticed and began cruising in the Bay of Bengal, capturing a few small vessels but making no serious impression on British trade in the region. By 1 June, Duperré had moved to the Western Indian Ocean, sailing off Madagascar in the hope of sighting British ships from Cape Town. Due to the extended period at sea, his ships were in a poor state of repair and much of the following month was spent conducting repairs at isolated beaches.

At 06:00 on 3 July, Duperré's squadron was cruising off the small island of Mayotta when sails were sighted 36 nautical miles (67 km) to the north east. Giving chase immediately, Duprée discovered that his quarry was a convoy of three British East Indiamen, Ceylon, Windham, under Captain Stewart, and Astell, commanded by Henry Meriton in Ceylon. Meriton was an experienced captain who had twice successfully defended convoys from French raiders: firstly at the action of 4 August 1800, when his ship Exeter had forced the surrender of the Médée, and then at the Battle of Pulo Aura in 1804. The convoy had departed from Cape Town on 13 June with five ships, but two had to turn back after Euphrates struck a rock and began to take in water. The others continued towards Madras via the Mozambique Channel. One of the East Indiamen, Windham, her captain John Stewart and many of her crew had been engaged and captured by Hamelin on 22 November 1809 in the Bay of Bengal and recaptured a month later by HMS Magicienne off Isle de France. While Duperré's three ships mounted 108 guns and carried trained naval crews, the British ships had approximately 75 cannon between them and only a handful of their sailors were trained to military standards. Primarily crewed by lascar seamen, who had proven unreliable in the previous convoy actions, the merchant ships' advantages lay in their large size and the 250 soldiers of the 24th Regiment of Foot that were aboard the ships. These troops were on passage to India and would be able to provide musket fire and repel boarders should the French attempt to board.