On 10 August 1519, the five ships under Magellan's command left Seville and descended the Guadalquivir River to Sanlúcar de Barrameda, at the mouth of the river. There they remained more than five weeks.

The fleet left Spain on 20 September 1519, sailing west across the Atlantic toward South America. Magellan's fleet consisted of five ships, carrying supplies for two years of travel. The crew consisted of about 270 men. Most were Spanish, but around 40 were Portuguese.