The first voyage of James Cook was a combined Royal Navy and Royal Society expedition to the south Pacific Ocean aboard HMS Endeavour, from 1768 to 1771. It was the first of three Pacific voyages of which James Cook was the commander. The aims of this first expedition were to observe the 1769 transit of Venus across the Sun (34 June that year), and to seek evidence of the postulated Terra Australis Incognita or "undiscovered southern land".

The voyage was commissioned by King George III and commanded by Lieutenant Cook, a junior naval officer with good skills in cartography and mathematics. Departing from Plymouth Dockyard in August 1768, the expedition crossed the Atlantic, rounded Cape Horn and reached Tahiti in time to observe the transit of Venus. Cook then set sail into the largely uncharted ocean to the south, stopping at the Pacific islands of Huahine, Borabora and Raiatea to claim them for Great Britain. In October 1769 the expedition reached New Zealand, being the second Europeans to visit there, following the first European discovery by Abel Tasman 127 years earlier. Cook and his crew spent the following six months charting the New Zealand coast, before resuming their voyage westward across open sea. In April 1770 they became the first known Europeans to reach the east coast of Australia, making landfall near present-day Point Hicks, and then proceeding north to Botany Bay.

The expedition continued northward along the Australian coastline, narrowly avoiding shipwreck on the Great Barrier Reef. In October 1770 the badly damaged Endeavour came into the port of Batavia in the Dutch East Indies, her crew sworn to secrecy about the lands they had discovered. They resumed their journey on 26 December, rounded the Cape of Good Hope on 13 March 1771, and reached the English port of Deal on 12 July. The voyage lasted almost three years.

The year following his return Cook set out on a second voyage of the Pacific, which lasted from 1772 to 1775. His third and final voyage lasted from 1776 to 1779.

James Cook (7 November 1728 – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean and to Australia in particular. He made detailed maps of Newfoundland prior to making three voyages to the Pacific, during which he achieved the first recorded European contact with the eastern coastline of Australia and the Hawaiian Islands, and the first recorded circumnavigation of New Zealand.

Cook joined the British merchant navy as a teenager and joined the Royal Navy in 1755. He saw action in the Seven Years' War and subsequently surveyed and mapped much of the entrance to the St. Lawrence River during the siege of Quebec, which brought him to the attention of the Admiralty and the Royal Society. This acclaim came at a crucial moment for the direction of British overseas exploration, and it led to his commission in 1766 as commander of HMS Endeavour for the first of three Pacific voyages.

In these voyages, Cook sailed thousands of miles across largely uncharted areas of the globe. He mapped lands from New Zealand to Hawaii in the Pacific Ocean in greater detail and on a scale not previously charted by Western explorers. He surveyed and named features, and recorded islands and coastlines on European maps for the first time. He displayed a combination of seamanship, superior surveying and cartographic skills, physical courage, and an ability to lead men in adverse conditions.

Cook was attacked and killed in 1779 during his third exploratory voyage in the Pacific while attempting to kidnap the ruling chief of the island of Hawaiʻi, Kalaniʻōpuʻu, to reclaim a cutter taken from one of his ships after his crew took wood from a burial ground. He left a legacy of scientific and geographical knowledge that influenced his successors well into the 20th century, and numerous memorials worldwide have been dedicated to him.