In 1917, the submarine was transferred to the east coast along with "CC-2" and the submarine tender . Their transit through the Panama Canal was the first time a Canadian or British warship traversed the Panama Canal under the White Ensign. They arrived at Halifax, Nova Scotia for preparation to send the two subs to Europe. Deemed unsafe for transatlantic crossing, "CC-1" was held in Halifax for coastal defence. While under repair at Halifax, the two submarines survived the Halifax Explosion unscathed. The Royal Canadian Navy then devised a plan to utilise the two subs in anti-submarine training for the surface vessels. The two subs finished the war as training vessels, not going on patrol again before the Armistice.