Private Rab Watson enlisted into the Army on 7 December 1944 and was sent to the 59th Primary Training Wing. After volunteering for airborne forces he was transferred to the Army Air Corps and posted to the Infantry Training Wing.On 21 April 1945 Rab was posted to the Army Air Corps Depot and later attended RAF Ringway for Parachute Training Course 163 which ran from 7 to 24 May 1945. He was initially posted to No 1 Parachute Regiment Reserve Battalion after qualifying as a military parachutist.

He embarked for India, arriving in Bombay on 22 July 1945 and was posted to the Independent Pathfinder Company of 44 Indian Airborne Division. In 1946, after a short spell at 10th RAF General Headquarters he was posted to the 16th Parachute Battalion and served with them until embarking at Bombay for the UK in August 1946.

Shortly after his return to the UK, Rab was released to the Army reserve in October 1946.