At the outbreak of war, the Regiment was based in Dublin, part of 3rd Cavalry Brigade, Cavalry Division before being rapidly deployed to France.
During September 1914, the Brigade transferred to the newly formed 2nd Cavalry Division.
The Division remained on the Western Front in France and Flanders throughout the war taking part in many major actions including:
Battle of the Aisne.
Battle of Messines.
Battle of Armentieres.
Battle of Gheluvelt.
Battle of Neuve Chapelle.
Battle of St Julien/Bellewaarde Ridge.
First Battle of the Scarpe.
Tank Attack at Cambrai.
Capture of Bourlon Wood/German counterattacks at Cambrai.
Battle of St Quentin.
Battle of Hazebrouck.
Battle of Amiens.
Battle of Albert/Second Battle of Bapaume.
Battle of the Canal du Nord/St Quentin Canal/Battle of the Beaurevoir Line/Battle of Cambrai.
Pursuit to the Selle,
Battle of the Sambre/Capture of Mons.
The Division then formed part of the Occupation Force in Germany before being disbanded during the spring of 1919.
The Victoria Cross was awarded to one man, who was serving with the 5th (Royal Irish) Lancers:
1914 - 31.
1915 - 25.
1916 - 20.
1917 - 31.
1918, up to 11th Nov - 57.