She sailed primarily as a West Indiaman until circa 1804 when Daniel Bennett purchased her and sent her out as a privateer operating off South America, first in the Atlantic and then the Pacific.

A Spanish armed merchantman captured her in 1805, in a single ship action that resulted in the death of Antelope's master.

[1][a] Although Bennett owned whaling ships and Antelope sailed for the South Seas, she was a privateer, not a whaler.

[5] Antelope may have returned to London because she was listed as being at Deal on 28 February, waiting to sail to the South Seas.

In her cruise near Montevideo Antelope took five prizes and forced the Spanish warship Asuncion aground in bad weather.

In sight of the island of San Gallao he seized two guano brigs, took their spars for firewood, removed their compasses, and prevented them from entering Callao and alerting the authorities to his presence.

In the fight Antelope suffered 15 men killed, Mortlake among them, and 16 wounded, most mortally.

[11][e] In October 1805, Viceroy Avilés ordered Antelope be transferred to the shipowner Javier María de Aguirre.

[15] Lloyd's List reported on 15 July 1806, that an armed Spanish ship had captured Antelope, of London, Mortlock, master, off the coast of Peru.