During the Second World War the Regiment was expanded to four battalions, 1st, 2nd, 3rd, and 10th, and all rendered sterling service.

The Regiment also put to good use their Vickers, Lewis and Bren machine guns to provide defence against low flying aircraft, especially those strafing the airfields.

As the few RAF fighter planes available would be scrambled to engage the enemy bombers, and since the prime targets were the airfields, the bomb craters would have to be filled in and passed over with a roller to allow the defending fighters to land again before they ran out of fuel.

Other jobs were the re-arming and refueling of planes, as well as the building of protective pens for the aircraft to minimize bomb shrapnel damage as much as possible.

The KOMR was frequently called upon to perform unenviable tasks such as when in January 1941, after the Germans tried to sink the Illustrious in port with determined and ferocious bombing, they were sent to rescue the living and remove the dead from the devastated Cottonera area of the Grand Harbour.

This pattern attempted to replicate the rubble walls that are still commonly used to separate fields and properties in Malta.