During the period 15 February-31 March 1778, "Boston", now under the command of Samuel Tucker, carried John Adams to France, capturing one prize en route. She then cruised in European waters taking four prizes before returning to Portsmouth, New Hampshire, 15 October. In 1779 she made two cruises (29 July – 6 September and 23 November – 23 December) in the North Atlantic capturing at least nine prizes. "Boston" then joined the squadron sent to assist in the defense of Charleston, South Carolina. There the British captured her when the town surrendered on 12 May 1780.