She started sailing out of London in 1795 as a slave ship in the triangular trade in enslaved people.

Defiance first appeared in Lloyd's Register (LR) in 1795 with J.Kimber, master, Parry & Co., owners, and trade London–Africa.

Dolben's Act was the first British legislation passed to regulate slave shipping.

Dolben's Act apparently resulted in some reduction in the numbers of captives carried per vessel, and possibly in mortality, though the evidence is ambiguous.

She gathered the captives first at the "Lamo River", and then at Cape Coast Castle.

She had embarked 401 captives and she delivered 399, for a mortality rate of less than 1%, which would qualify her master and surgeon for the full bonus.

Lloyd's List reported on 16 January 1801 that the French privateer Mouche had captured three vessels:[8][a] It is highly likely that this Defiance is the Defiance that British interests purchased in France in 1802 during the Peace of Amiens.