1/1st

August 1914 : Hertford, part of the Eastern Mounted Brigade.
10 September 1914 : sailed for Egypt.
19 January 1915 : joined the Yeomanry Mounted Brigade. This was originally an independent command. It moved in August 1915 to Gallipoli as dismounted troops, was placed under command of 2nd Mounted Division and was retitled as 5th Mounted Brigade.
December 1915 : withdrew from Gallipoli and returned to Egypt.
March 1916 : was split up:
RHQ and A Squadron joined 54th (East Anglian) Division. Joined XXI Corps Cavalry Regiment on 26 August 1917.
B Squadron joined 11th (Northern) Division in Egypt. Moved to France with Division, landing 4 July 1916. 12 July 1916 joined VI Corps Cavalry: in early 1917 it moved to XVIII Corps Cavalry Regiment; in May 1917 it became GHQ Troops; in July 1917 it returned to Egypt and in May 1918 joined XXI Corps Cavalry.
D Squadron moved to Mesopotamia, initially on Lines of Communication; in July 1916 it joined 13th (Western) Division and in December of that year it moved to III (Tigris) Corps Cavalry Regiment. In August 1917 transferred to the 15th (Indian) Division and in May 1918 went to the Lines of Communication in the North Persia Force.

2/1st

Formed on 1 September 1914 and remained in UK until May 1918 when moved to Ireland.
Converted into a cyclist unit in September 1917.
All fit men were sent as drafts to France in March 1918.

3/1st

Formed as a Third-Line training unit in 1915.
Remained in United Kingdom until until absorbed by 6th Reserve Cavalry Regiment in early 1917.