Meanwhile, the 2nd battalion embarked for Portugal in April 1809 for service in the Peninsular War. It saw action at the Second Battle of Porto in May 1809, the Battle of Talavera in July 1809 and the Battle of Bussaco in September 1810 before falling back to the Lines of Torres Vedras. It also took part in the First Siege of Badajoz in January 1811 and the Battle of Albuera in May 1811. At Albuera the battalion suffered heavy losses: 16 of its officers and 310 of its men killed, wounded or missing. It went on to fight at the Battle of Arroyo dos Molinos in October 1811 and the Battle of Vitoria in June 1813. It then pursued the French Army into France and fought at the Battle of the Pyrenees in July 1813, the Battle of Nivelle in November 1813 and the Battle of Nive in December 1813 as well as the Battle of Orthez in February 1814 and the Battle of Toulouse in April 1814. In July 1817 the battalion arrived in Saint Helena with orders to guard Napoleon who was in exile: the two battalions amalgamated again later that year.