Largest naval battle in history

Naming the largest naval battle in history depends on the definitions of "largest" and "battle." Potential criteria include number of people and ships involved, the total tonnage of vessels, the size of the battlefield, and the duration of the fight. There are three main candidates, each of which are said to have involved about 200,000 personnel: the Battle of Salamis, the Battle of Ecnomus and the Battle of Leyte Gulf.

The first two occurred in the Classical Era, when ancient sources frequently exaggerated the numbers involved in warfare. Herodotus claimed in The Histories that Xerxes invaded Greece with some 2,600,000 soldiers, but it is commonly believed that about 100,000-200,000 troops actually participated. Since Herodotus is one of the key sources for information on the Battle of Salamis, it is likely that it involved far fewer than the claimed 200,000 sailors and 1,642 vessels. Figures for the Battle of Ecnomus are similarly dubious. In contrast, the Battle of Leyte Gulf was fought during World War II, and one side was fielded by liberal democracies, with strong record-keeping institutions.

In pre-modern battles, large actions involved numerous small galleys, rather than larger vessels like battleships or cruisers. The largest number of ships of the line in a single battle was perhaps the 87 of various sizes which took part in a sea battle between Venice and Turkey near Corfu in 1716 (however, most didn't fight), or the 85 which took part in the Battle of Matapan, between Venice and Turkey, in 1717. Several battles of the First Anglo-Dutch War (1652-1654) as well as the Battle of Beachy Head in 1690 and the Battle of La Hougue in 1692 also featured large numbers of warships on each side, possibly well over 100, depending on where you draw the line between ships of the line and frigates. Most larger fleet battles involved 20-30 battleships, as well as smaller ships, on each side.

The candidates

The Battle of Salamis, 480 BC. 371 Greek ships defeated 1,271 Persian ships in this decisive battle. Greek triremes had a crew of about 200 while their small penteconters had 50 oarsmen. With 1,642 ships altogether, it seems that about 200,000 sailors, soldiers and marines may have taken part.
The Battle of Ecnomus, 256 BC. Like Salamis, Ecnomus was also a single engagement where 680 ships were fighting in a very small area. Some historians accept Roman claims that Rome had approximately 100,000 personnel. If this is true, it is probable that at least 200,000 Roman and Carthaginian sailors and soldiers were involved.
The Battle of Leyte Gulf, 1944. The largest in terms of tonnage of ships and also in terms of the area in which the action took place. United States and Australian forces included 17 large aircraft carriers, 18 smaller escort carriers, 12 battleships, 24 cruisers, 141 destroyers, smaller ships, and around 1,500 planes. They won a decisive victory over Japanese forces, which consisted of four aircraft carriers, nine battleships, 19 cruisers, 34 destroyers and other ships and around 200 planes. It is estimated that about 200,000 personnel were involved. Leyte Gulf was also a major air battle, and was the scene of the first use of kamikaze planes. It encompassed several distinct actions over the space of three days, all of them linked by the strategies of the Allied and Japanese commanders.