She arrived at Milford Haven, Wales, on 14 September for maneuvers with ships of other NATO navies in the Irish Sea, visiting Plymouth, England, and Brest, France, before returning to Newport 21 October 1957 to resume local operations.

Courtney sailed from Newport 1 April 1958 and called at Reykjavík, Iceland, on the way to Bodø, Norway, to conduct exercises with ships of the Royal Norwegian Navy.

From 7 August to 30 September, she was involved in Operation Argus, conducting nuclear tests in the high atmosphere as part of Navy Task Force 88.

Again cruising to South American waters from February through March 1959, she called at ports in Colombia, Ecuador, Peru, and Chile, and exercised with ships of the Colombian and Peruvian navies.

From August through December 1960, Courtney participated in Operation Unitas, the combined antisubmarine training cruise of the American nations.