In 1805 she sailed to the West Indies with Aigle where they joined a French fleet under Vice-Admiral Villeneuve. In October 1805 she took part in the Battle of Trafalgar, under Rear Admiral Charles Magon. She was engaged by HMS Tonnant at point-blank range, and Magon attempted a boarding, but the boarding party was annihilated by British fire which killed all but one of the party, who was made prisoner. Magon was killed. The fight went on for an hour with Tonnant's starboard guns duelling with the Algésiras, the port guns with Pluton, and the forward guns aimed at the San Juan Nepomuceno. Algésiras finally surrendered to Tonnant at around 14:30.