[3] On her first convict voyage, under the command of Robert Carns and surgeon Thomas Reid, Neptune departed The Downs on 20 December 1817 and arrived in Sydney on 5 May 1818.

On her second convict voyage, under the command of William McKissock (or M’Kessock, or M’Kessop) and surgeon J. Mitchell, she departed The Downs on 23 March 1820 and arrived in Sydney on 16 July 1820.

Neptune, M'Kessock, master, arrived at Cape Town on 7 September 1821 in a very leaky condition.

Resource, Fenn, master, was in November to carry the sound part of the cargo to England.

She was sold for 5010 rupees for breaking up, and on 11 December she arrived at Table Bay for demolition.