Underway on 11 April to patrol off Cap de Ca Mau, the southernmost tip of South Vietnam, Vance monitored coastal junk traffic and seagoing vessels, surveying traffic patterns in the South China Sea. Later, off Binh Dinh, she closed to investigate a trawler and came under fire from Viet Cong ashore. Although the ship's skin was pocked by bullets, Vance briskly returned the fire with her 3-inch battery, driving away or killing the unseen but pestiferous snipers.  

In a more humanitarian vein, Vance and a "Swift" rescued 56 men, women, and children from a swamped boat near Qui Nhon. For several hours, Vance's men cleaned and fed babies; made old women as comfortable as possible; and gave away blankets, towels, and food. Relieved by Haverfield (DER-393) late in July Vance headed for Hawaii and got as far as the San Bernadino Strait before she was ordered to return to Vietnam for further "Market Time" duty. On 6 August, Surfbird (ADG-383) relieved the destroyer escort on station and allowed Vance to sail again via the Philippines for Pearl Harbor.