Following her shakedown training out of Bermuda, "Bull" escorted the Army transport USAT "George Washington" to Norfolk, Virginia, and then continued on to Boston, Massachusetts, where she arrived on 4 October 1943 for post-shakedown availability. The destroyer escort touched briefly at New York City; proceeded thence to Curaçao, in the Dutch West Indies, and then headed across the Atlantic to Derry, Northern Ireland, on her first convoy-escort mission. Following her return to New York on 9 December, "Bull" operated out of Cape Cod Bay through the end of 1943 with Fleet Air, Atlantic, towing targets used by Navy planes practicing radar and dive-bombing tactics.