"Prinz Heinrich" served with the German fleet for the majority of her career. After the outbreak of World War I in August 1914, the ship participated in an operation against the British coast in December 1914, after which she was transferred to the Baltic Sea. Here, she operated against the Russian navy and was involved in the Battle of the Gulf of Riga in August 1915, where she damaged a Russian destroyer. In 1916, the ship was withdrawn from active duty and was used in several secondary roles in Kiel, including acting as a floating office for naval staff. "Prinz Heinrich" was ultimately sold in 1920 and broken up for scrap later that year.