Duarte Barbosa's brother in law, strengthening the links between the Barbosa and Magellan families.

On 10 August 1519 Duarte Barbosa sailed from Seville on Magellan's voyage of circumnavigation, along with his friend João Serrão. His curiosity led him to leave the expedition for the company of locals several times during the voyage, to Magellan's annoyance. Magellan even came to arrest him. On 2 April 1520, however, the help of Duarte Barbosa was crucial to facing down a riot in Puerto San Julian