On 4 May 1951, the regiment mobilized two temporary Active Force companies designated "E" and "F" Company. "E" Company was reduced to nil strength upon its personnel being incorporated into the 1st Canadian Highland Battalion (which later became the 1st Battalion The Black Watch (Royal Highland Regiment) of Canada) for service in Germany with the North Atlantic Treaty Organization. "F" Company was initially used as a reinforcement pool for "E" Company. On 15 May 1952, it was reduced to nil strength, upon its personnel being absorbed by the newly formed 2nd Canadian Highland Battalion (which later became the 2nd Battalion The Black Watch (Royal Highland Regiment) of Canada) for service in Korea with the United Nations.