The first documented European contact with Hawaii was by Captain James Cook in 1778. However, the islands were discovered and settled centuries earlier by Polynesian voyagers.
Tupaia was a Tahitian priest, navigator, and translator who joined Cook's Endeavour expedition in 1769. His deep knowledge of Pacific geography, star paths, and island networks was invaluable. While Tupaia did not "discover" Hawaii (he died in Batavia in 1770, before Cook's third voyage reached Hawaii), he represents the indigenous navigational expertise that made Polynesian expansion possible.
Cook's arrival began written history and Western contact, but the true discovery and peopling of Hawaii belongs to the Polynesian navigators whose oral traditions and wayfinding science achieved one of humanity's greatest feats of exploration.