Effective sailed from New Orleans, Louisiana, on 11 November 1942, and called at Key West, Florida, and Charleston, South Carolina, before arriving at Norfolk, Virginia, 8 January 1943. After intensive training, she arrived in Bermuda in February. She remained there on patrol and local escort, with occasional escort voyages to ports on the east coast, until 7 July 1944. Sailing from Bermuda she rendezvoused with a convoy bound for the Mediterranean.