Details of his early life are sparse. Magellan was born in about 1480, at Salrosa, in northern Portugal, the son of a provincial nobleman, he spent his childhood in the house of Queen Leonora, wife of Henry II. When he was twelve, he came to Lisbon to serve as a page at the court of John II, where he met Francisco Serrao.
Magellan and Serrao were promoted to the rank of squire and began service in the Marine department at Lisbon. Magellan was responsible for providing supplies for Portuguese ships and probably also acquired a knowledge of navigation.
In 1505 he began his career at sea, apparently as an ordinary seaman, sailing with the fleet commanded by Francisco de Almeida on a mission to consolidate and extend Portuguese interests in the East. He distinguished himself and won promotion, rescuing some companions and helping to avert a mutiny.
In 1509 he was wounded at the battle of Diu. Later that year Magellan sailed for the strategic port Malacca with the first Portuguese fleet to visit. He was still in the east in 1511, when he took part in the six-week siege that resulted in the Portuguese conquest of Malacca.
When Malacca fell, the Portuguese gained control of the wealth that passed through its markets, and the trade of the Spice Islands. Magellan may have been wounded in action. From his new base, Albuquerque sent missions out in search of the Spice Islands.
Magellan took part in Abreu’s expedition as captain of a caravel, the first such post he had received after working his way through the ranks without the help of patronage or favouritism.
Serrao, who also served with d'Albuquerque's expedition, settled on Ternate as an adviser to the Sultan and his letters may have played a part in encouraging Magellan to seek the islands for himself.
Magellan returned to Portugal, but financial difficulties forced him out of retirement.