With the outbreak of the First Balkan War in October 1912, the Greek fleet under Rear Admiral Pavlos Koundouriotis seized the strategic island of Lemnos at the entrance of the Dardanelles Straits, and proceeded to establish a naval blockade of the Straits. With the Ottoman fleet confined behind the Daradanelles, the Greeks were left with complete control of the Aegean Sea, and began occupying the Ottoman-ruled Aegean islands.^[51] Most of these islands had few or no troops, apart from the larger islands of Chios and Lesbos; the latter was garrisoned by the 2nd Battalion of the 18th Infantry Regiment.^[52] The Ottoman garrison numbered 3,600 men, of whom 1,600 were professional soldiers, with the rest being irregulars and drafted Christians, commanded by Major Abdul Ghani Pasha whose headquarters were based in Molyvos.^[53]

As a result, the Greeks delayed moving against Chios and Lesbos until operations were concluded on the main front in Macedonia and forces could be spared for a serious assault. With rumours of a cease-fire circulating in late November, the speedy capture of these islands became imperative. Another factor was Bulgaria's rapid advance in Thrace and eastern Macedonia. Τhe Greek government feared that Bulgaria may use Lesbos as a bargaining chip during the course of future peace negotiations.^[54] An ad hoc force was assembled for capturing Lesbos: naval infantry detachments were gathered at Mudros Bay and boarded on the cruiser Averoff and the steamer Pelops, along with some light naval artillery and two machine guns. Setting sail for Lesbos on 7 November 1912, the landing force were joined on the way by a newly raised reservist infantry battalion (15 officers and 1,019 men) from Athens.

The Battle of Lesbos took place from 21 November – 21 December 1912 during the First Balkan War, resulting in the capture of the eastern Aegean island of Lesbos by the Kingdom of Greece.