While participating in Operation Deep Freeze I during the winter (Antarctic summer) of 1955–1956, "Edisto" penetrated unexplored areas in the Antarctic near Cape Hallett, leaving "Edisto Bay" and "Edisto Acres" penguin rookery named in her honor. After her return to Boston the ship was again assigned to Arctic missions, aiding shipping in the Newfoundland and Labrador area for the remainder of 1956 and all of 1957. In December 1958, "Edisto" departed for Operation Deep Freeze IV. Her work in the Antarctic this time was in support of the International Geophysical Year. From April 16–26, 1959, while en route home, she stopped in Montevideo, Uruguay, which was experiencing disastrous floods. The crew labored many long hours in flood relief work, rescuing 227 persons by helicopter, thereby receiving the personal thanks of the president of Uruguay on their departure.