August 1914 : headquarters and B” Squadron in Barnstaple; “A” Squadron in Holsworthy; “C” in South Molton; “D” in Torrington. Under command of the 2nd South Western Mounted Brigade.
October 1915 : dismounted and moved to Gallipoli. Withdrew back to Egypt on 30 December 1915.
February 1916 : Brigade was absorbed into 2nd Dismounted Brigade.
4 January 1917 : merged with Royal 1st Devonshire Yeomanry to form the 16th (Royal 1st Devon and North Devon Yeomanry) Bn, the Devonshire Regiment and came under orders of 229th Brigade in 74th (Yeomanry) Division. Moved to France, landing at Marseilles 7 May 1918.
Formed as a Second-Line regiment in September 1914 and remained in UK until in November 1916, converted into a Cyclist unit and redesignated 4th Yeomanry Cyclist Regiment. Resumed original identity in March 1917. Moved to Ireland in May 1918.
Formed as a Third-Line training unit in 1915.
Remained in United Kingdom until disbanded in early 1917.