Spread across several different transport vessels, after completing the crossing - during which the battalion's machine guns were employed for anti-aircraft defence - the 2/1st's companies were split up: 'A' Company, supported the Australian 2/4th Battalion, while two companies - 'B' and 'C' - supported the New Zealand 4th Brigade, and another - 'D' Company - was assigned to the Australian 17th Brigade. The campaign proved to be short-lived, as the Allies were quickly pushed back by the advancing Germans, and the battalion was subsequently withdrawn around the end of April and early May, having fought major actions around the Aliakmon River, Servia Pass, Lamia and Mount Olympus. During the evacuation, elements of three companies were taken aboard the transport Costa Rica, which was later attacked by German aircraft. As the vessel was sinking, the troops on board were evacuated by Royal Navy destroyers and landed on Crete, minus the majority of their equipment which was lost at sea.