Between 1789 and 1791 she served as a storeship, carrying provisions to the convict settlement at New South Wales.

Justinian first appeared in Lloyd's Register (LR) in 1790 with Maitland, master, Hamilton, owner, and trade London–Botany Bay.

Captain Benjamin Maitland sailed Justinian on 29 December 1789,[1] and she left Falmouth, England, on 20 January 1790, bound for New South Wales and China.

She had arrived at the Sydney Heads one day before Lady Juliana and only ill winds had prevented her from entering.

After unloading, she departed for China on 28 July 1790,[4] to load tea for the EIC for the return journey to Britain.