During the period of tension before the outbreak of war, the 9th Battalion sent two special service sections to guard a cable station at Cuckmere Haven and Birling Gap (28 July). When the mobilisation orders were received on 4 August 1914, the Home Counties Division was on the march from Aldershot to Salisbury Plain for its annual training. The Middlesex Brigade had reached Larkhill, when the battalions were sent back to their headquarters to mobilise. The 9th Battalion entrained at Amesbury on 5 August and reached Willesden that morning. By the end of the day the battalion was entrained again for its war station at Sheerness. Here it dug trenches for a few days until relieved by Special Reserve troops and moved to Sittingbourne.