Trippe spent the remainder of 1939 outfitting at Boston. In January 1940, she visited Newport, R.I., to take on torpedoes and Yorktown, Va., to load depth charges before heading for the Gulf of Mexico. Following shakedown training in the Gulf of Mexico and the Caribbean, she returned to Boston on 20 March 1940.

After completing her post-shakedown overhaul, Trippe departed Boston on 24 June ultimately to join the Caribbean portion of the Neutrality Patrol. She voyaged via Hampton Roads to San Juan, Puerto Rico, where she arrived early in July only to return north at mid-month for a two-day visit to Washington, D.C. On 26 July, Trippe entered San Juan once more to begin Neutrality Patrol duty in earnest.

For eight months, the destroyer roamed the warm waters of the West Indies to prevent the European belligerents from waging war in the western hemisphere. During that period, she escorted Tuscaloosa (CA-37), with President Roosevelt embarked, on a tour of bases in the Caribbean. She saw the President safely into Charleston, S.C., on 14 December and then headed for Philadelphia and quick repairs. After a two day visit to Norfolk at the end of the first week in January 1941, Trippe steamed south to Guantánamo Bay, Cuba, where she conducted neutrality patrols until spring. (continued)