During the first 15 months of her active service, the motor minesweeper operated along the east coast of the United States. In July 1944, she voyaged across the Atlantic Ocean to participate in the invasion of southern France and, but for refueling and replenishment breaks at Corsica, remained off that coast sweeping mines from the first assaults on the morning of 15 August until 21 September. At that time, she moved to Palermo, Sicily, where she performed additional minesweeping duties. "YMS-164" continued to serve at various locations in the Mediterranean through the end of hostilities in Europe.