In 1588 he seems to have commanded "Black Dog" against the Spanish Armada. In 1589 he joined the Earl of Cumberland as part of the Azores Voyage of 1589. In 1591 he accompanied Thomas Cavendish on Cavendish's last voyage, which sought to discover the Northwest Passage "upon the back parts of America" (i.e., from the western entrance). After the rest of Cavendish's expedition returned unsuccessful, Davis continued to attempt on his own account the passage of the Strait of Magellan; though defeated by foul weather, he apparently discovered the Falkland Islands in August 1592 aboard "Desire". His crew was forced to kill hundreds of penguins for food on the islands, but the stored meat spoiled in the tropics and only fourteen of his 76 men made it home alive.