On 18 May 1942 Borg Pisani volunteered for an espionage mission to Malta, to check British defenses and help prepare for the planned Axis invasion of the island (Operation Herkules). He disembarked at the Dingli Cliffs in Ras id-Dawwara, and transferred all his rations to a cave that he knew well from his youth. Unusually inclement weather and a rough sea, however, washed all his possessions away within 48 hours, and he proved unable to climb the cliffs. He was forced to wave down a local boat. Upon rescue by a British patrol boat, he was brought to the naval hospital RNH Mtarfa.