3rd EIC voyage (1793–1794): War with France had broken out shortly before "Marquis of Lansdown" sailed on her third voyage. Captain Joseph Boulderson acquired a letter of marque on 2 April 1793. He sailed from Portsmouth on 22 May, bound for Madras and Bengal. "Marquis of Lansdown" reached Madras on 16 September and arrived at Diamond Harbour on 4 November. Homeward bound, she was at Saugor on 11 January 1794, reached St Helena on 18 June, and arrived at the Downs on 7 September.