Wimberley's company fought in the Battle of Passchendaele (also known as the Third Battle of Ypres). In November he was wounded and awarded the Military Cross during the Battle of Cambrai. In early 1918 the four machine gun companies of the division were merged into the 51st Machine Gun Battalion, resulting in his company being retitled as 'D'Company. On 18 February 1918 Wimberley was promoted to the acting rank of major. The German Army launched its Spring Offensive in late March and Wimberley was again wounded and, evacuated to England, was passed fit for service in June and attended a machine gun refresher course at Grantham the following month, but was not to see any further action during the war. He was soon afterwards posted as a company commander in the 9th Reserve Battalion, Machine Gun Corps, a training unit. In October/November he attended a Royal Air Force (RAF) cooperation course, with the intention of training infantry officers to be air observers. He was there by the time of the Armistice with Germany in November, which brought the war to an end.