The title of "largest naval battle in history" is disputed between adherents of criteria which include the numbers of personnel and/or vessels involved in the battle, and the total tonnage of the vessels involved. While battles fought in modern times are comparatively well-documented, the figures from those in pre-Renaissance times are generally believed to be exaggerated by contemporary chroniclers.
Salamis, September (28?) 480 BC. 371 Greek ships defeated 300–600 Persian ships in this decisive battle. Greek triremes had a crew of about 200 while their small penteconters had 50 oarsmen, which would suggest that approximately 200,000 sailors, soldiers and marines took part.
Cape Ecnomus, 256 BC. One of Rome's first major naval victories over its rival, the city of Carthage, in the First Punic War. The battle itself involved around 680 ships and 300,000 personnel from both sides. Total casualties were about 40,000–50,000, of which roughly 10,000 were on the Roman side and the rest from the Carthaginian side.
Red Cliffs, winter AD 208. A decisive naval engagement between the forces of Cao Cao and the allied forces of Liu Bei and Sun Quan, this battle resulted in the defeat of Cao Cao and confirmed the separation of China into northern and southern halves, the Yangtze River Valley as a border. Between 270,000 and 850,000 personnel participated in this battle.
Lake Poyang, August 30–October 4, 1363. Claimed to be the largest naval battle in terms of personnel, with a reported 850,000 sailors and soldiers involved. A Ming rebel force, said to be 200,000 strong, commanded by Zhu Yuanzhang, met a Han rebel force, claimed to be 650,000-strong, commanded by Chen Youliang, on Lake Poyang, China's largest freshwater lake.
Lepanto, 7 October 1571. 212 Holy Leaguegalleys and galleasses against 272 or more Ottoman galleys, galliots etc. (484+ total). The forces of the Holy League inflicted a crushing defeat on the Ottoman fleet. This was the last major naval battle in the Western world to be fought entirely or almost entirely between rowing vessels, and one of the earliest for which there is a reliable count of ships and personnel involved. Around 150,000 personnel took part in the battle. The Turkish fleet lost more than 200 vessels and suffered at least 20,000 casualties.
Jutland, May 31–June 1, 1916. The Imperial German Navy's High Seas Fleet commanded by Vice-Admiral Reinhard Scheer and the British Grand Fleet under Admiral Sir John Jellicoe engaged in battle near Jutland, Denmark during World War I. The German fleet consisted of 16 dreadnought and 6 pre-dreadnought battleships, 5 battle cruisers, 11 light cruisers, and 61 fleet torpedo boats, while the numerically superior British fleet was composed of 28 battleships, 9 battle cruisers, 8 armoured cruisers, 26 light cruisers, 78 destroyers, 1 minelayer, and 1 seaplane carrier. Britain lost more ships and twice as many men as Germany, although ultimately the outcome was beneficial for the British as the battle resulted in the successful containment of the German fleet. In terms of total tonnage of ships involved, this was the largest surface battle.
Philippine Sea, June 19–20, 1944. The largest aircraft carrier battle in history, involving fifteen U.S. fleet and light carriers, nine Japanese carriers, 170 other warships and some 1,700 aircraft. The U.S. Fifth Fleet's Task Force 58 is (in terms of tonnage) the largest single naval formation ever to give battle.