On 1st Aril 1939 the order was given to double the size of the Territorial Army. The 4th Battalion became the 1/4th in central Hampshire and the 2/4th in the north of the county. The 5/7th was divided back into its original components of the 5th Hampshire (from Southampton) and 7th Hampshire, (from Bournemouth and the New Forest).
After war was declared, the 2nd Battalion went to France with the British Expeditionary Force (BEF), returning to the UK in June 1940 after the retreat via Dunkirk. The Territorial Battalions were mobilised, initially to guard vital points such as Southampton Docks and important military installations in the Portsmouth area and on the Isle of Wight. In 1940, battalions were sent to defend the coast against likely invasion by the German army. When the threat subsided after the RAF won the Battle of Britain, all Battalions settled down to train for the future.
The 2nd Battalion was the first to go overseas in November 1942, joining the 1st Army in North Africa. 3 Territorial battalions followed a month later. These 4 battalions were to remain overseas, in action in Sicily, Italy, Greece, and Crete and as occupation troops in Austria until 1946 and after. The 7th Battalion remained in UK until it sailed for Normandy in June 1944, before taking the role of occupation troops in Germany in 1946.