On 21 May 1777, Boston sailed in company with Hancock for a cruise in the North Atlantic. The two frigates captured three prizes including the 28-gun frigate HMS Fox (7 June). Boston, Hancock, and Fox were engaged (7-8 July) by HMS Flora, Rainbow, and Victor. Her consorts were taken by the British squadron, but Boston escaped to the Sheepscot River on the Maine coast.
During 15 February-31 March 1778 Boston carried John Adams to France, capturing one prize enroute. 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, and was captured there by the British when the town surrendered 12 May 1780.
(Fr.: T. 514; l. 114'3"; b. 32'; dph. 10'3"; s. 8.5 k; a. 5 12-pdr. S. B., 19 9-pdr. S. B., 2 6-pdr. S. B., 4 4-pdr. S. B.)