The 2nd Battalion was called out on service on 26 August 1939 and details of the battalion were placed on active service on 1 September 1939, under the designation '2nd Battalion, The Black Watch (Royal Highland Regiment) of Canada, CASF (Details), for local protection duties. The details called out on active service were disbanded on 31 December 1940.
The regiment mobilized the '1st Battalion, The Black Watch (Royal Highland Regiment) of Canada, CASF' for active service on 1 September 1939. This unit, which served in Newfoundland from 22 June to 11 August 1940, embarked for Great Britain on 25 August 1940. On 6 July 1944, the battalion landed in France as part of the 5th Infantry Brigade, 2nd Canadian Infantry Division, and it continued to fight in North West Europe until the end of the war. The overseas battalion was disbanded on 30 November 1945. Source: Canada.