In July 1899, after less than a year at St Peter's, Eustace Hill volunteered as a chaplain in the event of war breaking out between the Boers and the British. After the Boer War had broken out in September of that year, Hill was attached to Lord Methuen's column. This column was sent to relieve the siege of Kimberley and later Mafeking. During this time, he was involved in ministering to the British soldiers at Modder River and Magersfontein, two of the major battles in this theatre of the war. In April 1900 Hill became sick with fever and returned to England on three months' sick leave.