The Regiment under Colonel William Seymour sailed from Cork in June 1701. In February 1702, William Seymour transferred to the Queen's Regiment and John Churchill, Duke of Marlborough, Commander-in-Chief of King William's forces on the Continent and one of England's greatest soldiers, took over as Colonel of the Regiment. The Regiment served throughout the War of the Spanish Succession and fought at the famous battles of Blenheim (1704), Ramillies (1706), Oudenarde (1708) and Malplaquet (1709).

Marlborough was the first senior commander who really cared for the welfare of his troops. This Marlborough tradition, maintained over the years, has helped to foster the family spirit that has always been a marked feature of the Regiment and has led to many outstanding achievements.