Which explorer is credited with the first European sighting of mainland Australia?

Willem Janszoon is credited with the first European sighting of mainland Australia. In 1606, he commanded the Dutch ship Duyfken on a voyage from the Dutch East Indies to investigate New Guinea and nearby lands.

After crossing the Arafura Sea, Janszoon reached the western coast of Cape York Peninsula in northern Queensland. On 26 February 1606, his crew made landfall near the Pennefather River, close to present-day Weipa. This is regarded as the first recorded European landing on the Australian continent, and the expedition charted roughly 320–350 kilometres of coastline.

Janszoon did not understand that he had reached a separate continent. He believed the coast was connected to New Guinea, partly because the expedition missed the Torres Strait. Spanish navigator Luís Vaz de Torres sailed through the strait later in 1606, but there is no firm evidence that he saw the Australian mainland.

Dirk Hartog reached western Australia in 1616, while James Cook charted the east coast in 1770. Those later voyages were important, but neither explorer made the first recorded European sighting.