1/1st

August 1914 : in Worcester. Part of the 1st South Midland Mounted Brigade, attached to 1st Mounted Division.

Moved with Brigade to 2nd Mounted Division in August 1914, and moved with them to Egypt, landing at Alexandria on 24 April 1915.

Landed at "A" Beach, Suvla Bay on Gallipoli, 18 August 1915. Took part in attack on Hill 112 on 21 August, advancing over 2 miles under heavy shrapnel fire.

Severe sickness, together with casualties, resulted in temporary reorganisation together with 1/1 Gloucestershire and 1/1/ Warwickshire Yeomanry, to form 1st South Midland Regiment, 1st Composite Mounted Brigade, in early September 1915.

Continued in trench warfare activities in Green Hill and Chocolate Hill sectors until evacuated to Mudros on 31 October 1915.

Moved with Brigade to Imperial Mounted Division in February 1917 (this was redesignated as Australian Mounted Division in June 1917).

Left Brigade to become XX Corps Cavalry Regiment.

2/1st

Formed September 1914, and remained in UK until going to Ireland late in the war. Initially attached to 2/1st Mounted Brigade, which was attached to to 2/2nd Mounted Division in June 1915. In March 1916, Brigade was redesignated 10th Mounted Brigade, in 3rd Mounted Division. In July 1916, converted into a Cyclist unit and attached to 8th Cyclist Brigade of 2nd Cyclist Division. The latter was broken up in November 1916, and the Regiment became half of the 12th (Gloucestersire and Worcestershire) Yeomanry Cyclist Regiment, attached to 4th Cyclist Brigade. The latter moved to Ireland in April 1918.

3/1st

Formed in 1915. Remained in United Kingdom until absorbed into 4th Reserve Cavalry Regiment in early 1917.