Neptune was one of the notorious Second Fleet ships to Port Jackson. Built in the River Thames in 1779, at 809 tons she was the largest ship of the fleet. In company with Surprize and Scarborough she sailed from England with 421 male and 78 female convicts on 19 January 1790. Her master was Donald Traill and surgeon was William Gray. She arrived at the Cape of Good Hope on 13 April 1790, and spent sixteen days there, taking on provisions, and twelve male convicts from HMS Guardian which had been wrecked after striking an iceberg. She and Scarborough were parted from Surprize in heavy weather and arrived at Port Jackson on 28 June 160 days out from England. During the voyage 158 convicts died (31%) and 269 (53%) were sick when landed.