During the Greek War of Independence, the sea was a crucial battlefield. Greeks were traditionally a naval people and had developed on the eve of the Revolution (1821) a remarkable merchant marine, as well as rich war experience due to their service in mercenary, pirate and corsair ships. They had also been obligated by the Ottomans to man the Ottoman fleet.

On the islands, there was a powerful social class of ship-owners and captains, favored mainly by the Treaty of Küçük Kaynarca (1774) which allowed Greek ships to hoist the Russian flag and move freely.The dissolution of the Venetian Republic by the French (1797) and the English-French rivalry during the Napoleonic Wars (1792-1815), contributed to the rapid growth of Greek merchant shipping.

All the Ottoman-occupied Greek islands participated to the Revolution. Most notable was the contribution of the three most powerful: Hydra, Spetses and Psara Islands, which, apart from the large number of ships, they also provided financial and administrative support. Merchantmen were quickly converted into battleships.With an aggressive strategy, they managed to control the sea routes, to block the Straits of the Dardanelles where the massive Ottoman fleet was confined, to impose and break sieges and to create diversion to land campaigns.

Later during the Revolution, Greek domination of the seas retreated because of economic difficulties, the civil war (1824-1825) and the intervention of the organized and war-trained Egyptian fleet.