Mexico and Caribbean brought the ship and her crew to a high degree of readiness before she sailed for her 3rd Mediterranean deployment early in 1967. She cruised the Mediterranean until returning to Norfolk in May. At mid-year she operated in the North Atlantic. After the upgrade in Bath, Maine, in 1969, the Yarnell made her way to Boston Naval Shipyard. The Yarnell was given a new crew and recommissioned for service in Boston. The Yarnell was then assigned to Naval Station Newport. A year of testing all the new systems and the Yarnell set sail in July, 1970 on a UNITAS cruise for exercises with the naval forces of South American countries. Following departure from Newport and an overnight visit at Dam Neck, VA, Yarnell sailed to San Juan, Puerto Rico to pick up the admiral for the cruise. The Yarnell visited Caracas, Venezuela; and Salvador, Rio de Janeiro (twice) and São Paulo, Brazil. A scheduled visit to Montevideo, Uruguay was cancelled due to political activity there, so Yarnell returned to Rio de Janeiro for a second visit. Following a stop in Comodoro Rivadavia, Argentina to take on supplies, Yarnell proceeded through the Magellan Straits and the Chilean Waterway into the Pacific Ocean, where stops were made in Chile, Peru, Ecuador, and Panama before going through the Panama Canal and returning to Newport via San Juan and St. Thomas, U.S. Virgin Islands. In late 1972, the Yarnell was again deployed to the Mediterranean. On the way across the Atlantic a helicopter from a Russian cruiser flew around the Yarnell taking many photographs. The Yarnell was ordered to accompany the Russia submarines from the Strait of Gibraltar to the Black Sea. Yarnell made port visits at Naples, Genoa, and Venice, Italy; Nice, France; Mallorca, Valencia and Barcelona, Spain; and Athens, Corfu, Rhodes, and Kavalla; Greece. Yarnell returned to the Mediterranean in August 1973. En route she visited Lisbon, Portugal, then took part in Exercise Quickshave off the coasts of France, England and Portugal, followed by turnover in Rota with the . Yarnell then deployed to La Palma, followed by Western Med operations as a picket with a short return afterward, to Palma. Group Operations off Crete along with an ORE, were followed by a trip to Athens. Further visits to Barcelona and Malaga occurred before turnover in Rota to on 14 January, Yarnell returning to Newport on 24 January 1974.