On 10 August 1804, pre-eminent English scientist Joseph Banks sent a letter to William Kerr, a King’s Gardener at Kew Gardens, appointing him to collect biological specimens of potential ornamental and medicinal value along the coast of China. Upon his arrival in Macau, local authorities deemed it too dangerous to conduct an expedition along the Chinese coast because of the threat from Chinese pirates. Instead, the authorities sent Kerr to the Philippines to collect specimens there. Kerr arrived in Manila in early February 1805. Over the next few months he collected many specimens, principally from a journey that took him around the complete circumference of Laguna de Bay. Kerr returned to Macau at the end of August, where his expedition met unexpected tragedy and loss of the collection. But the journal of his ill-fated expedition was traced by the first author to have been kept at the Library of the British Museum of Natural History. This paper summarizes the findings of Kerr during his expedition, including background about other significant events occurring during this period drawn from the first author’s previous research and referenced in the Kerr Journal. The second author places this expedition in historical context and presents an evaluation of the significance of the catalog of specimens collected by Kerr, which forms part of the journal.